Sometimes, your back itches slightly and scratching it at that perfect spot fills you with an odd sense of happiness. Other times, you notice a biting itch on your arm and a chickpea-like redness shows up there. Oh, those mosquitoes! It is rarely likely to catch a mosquito in the act, and sometimes it even feels as if their bites just appear out of thin air. As you scratch the blister to soothe the itchiness, your eyes scan the room to locate its infamous proboscis. You see it on a wall, plump with the blood it sucked from you. You cannot help thinking: Why do their bites always leave so much itching? Or even, what is the purpose of itching at all?

Itching is an unpleasant feeling we perceive by our skin and mucous membranes, and an occasionally uncomfortable and sometimes very excruciating feeling.

Itching, just like pain, is a sensation intrinsic to our body to protect itself [1].  It is the way our skin “talks” to us. Indeed animals, even fish, itch too. When itched, our skin instinctively and in its own tongue tells us, “There is something that bothers me and I want you to push it away from me immediately!” If it was not for itching, we would not notice a spider walking on our arm. We would not be disturbed by lice and scabies mites or even fungi that settled on our skin, and we would not try to protect ourselves from these pests either.

An ordinary scabies patient has an average number of about 15-20 adult scabies mites on their skin. In the case of Norwegian or crusted scabies, which is most commonly observed among the elderly, the bedridden, people with seriously weakened immune systems, or those who are unable to itch themselves sufficiently, there are thousands of parasites under the thick crusts of the skin [2]. Itching accelerates the blood circulation on the itched parts, and tissues virtually prepare to fight infection by the rushing blood cells and substances [3]. Yet, millions of people also suffer from chronic itching and scratch their itches much more than usual. To understand this, we need to set on a journey from our skin to our brain.

Human skin consists of three layers: epidermis, dermis and subcutis (also known as hypodermis). The dermis layer in the middle makes glove-like protrusions upward into the epidermis. At the top of these protrusions are mechanoreceptors and nerve endings that allow our skin to sense stimulus (such as temperature, sharpness, pressure, vibration, pain, or itching) [3]. With these receptors, our skin functions as one of our five sensory organs and more like an “alarm system” of our body against changing conditions outside. This alarm system has been created so perfectly that each component knows exactly what stimulus to detect.

Previously, it was thought that pain and itching were sensed by the same receptors (nociceptors) and that mild stimuli were responsible for itching while strong stimuli were responsible for pain [4]. Yet, a contradiction existed because while pain triggered an avoidance reflex, itching activated the scratching reflex. In recent years, it was discovered that the receptors (pruriceptors) that perceive the itching sensation on the skin are the free boundary terminations of C-fibers with myelin-free, slow conduction velocity extending in the form of tree branches toward the upper layer of the skin. Furthermore, it was found that the skin cells themselves behave like itch receptors [3, 4]. When we receive a stimulus that induces itching, such as a mosquito bite which leaves anticoagulant substances on our skin, the mast cells in the skin tissue spring to defense against those alien substances. This ensues the secretion of the bodily defense system called mediators, substances that are produced and stored by mast cells as precursor for emergency conditions. Histamine is the most known of these substances and is the most important mediator in itching conditions [5]. Histamine binds to receptors found for itself in myelin-free C fibers that are tasked for detecting itching on the skin. If we consider histamine as a key, the lock that it fits into is on the nerve that senses itching. Thus, the itching nerve is stimulated by histamine.

The nerves receiving this stimulus connect to the spinal cord at their respective levels and transfer the message to another nerve. Each of these transfer processes is mediated neurotransmitters. The last message transmitted to the brain through these nerves is assessed by the brain and labeled as “itching” [6]. The brain determines the coordinates of the itching location and orders the scratching action to the related muscle system. A new journey that conveys messages from the brain to the arm muscles ends with scratching. Considering the swift rubbing action when we feel an ant walking on our face and scratch to push it away, we may value how fast and perfect our brain and transmission system work.

It is also rather odd how soothing itching can be despite its initially uncomfortable feeling, almost as if our body is rewarding us for saving it from a threat. There are several reasons for this contradiction. Scratching causes a low-intensity pain on the skin. Pain and itch are positioned on the skin alternately. The transmission of the sensation of pain is prioritized while the transmission of itching is prevented [7]. Consequently, our brain senses the pain and, in response, secretes the hormone called serotonin to soothe the body. Although this makes us feel relaxed for a short time, the brain continues to transmit virtual sense of itching by connecting to the receptors that are located on the spinal cord along the same nerve path with the receptors for serotonin [8]. This condition, which may be termed as a vicious cycle of itching-scratching, unsurprisingly infuriates patients. Scratching the same area on the skin continuously causes the production of new mediators and oversensitivity of itching nerves, which can thus turn itching into a chronic distress. Chronic itching can often result as a complication from skin diseases such as scabies, lice, eczema, fungal diseases, or drug allergies. It can also result from a systemic disease such as chronic renal failure, cholestatic liver diseases, thyroid problems, iron deficiency anemia, blood diseases and, rarely, cancers [7]. Itching in systemic diseases can be triggered by mediators on the skin but also by neurotransmitters in the intermediate pathway. This kind of itching cannot be controlled by drugs called antihistamines which block the histamine pathway. Sometimes the brain will receive false itching alarms due to post-shingles contraindications or nerve damage in the vertebrae. Such episodes of itching need to be addressed to prevent adverse outcomes. At times, the reason an itch can occur can even be psychological when there seems to be no need for an itch. According to research, scratching activates the brain’s reward center which triggers the addiction mechanism. Patients in that case are thrilled as they itch constantly [9].

As doors in this mysterious journey of science are opened one after another, we discover that nothing has been created without a purpose, including apparently discomforting sensations such as itching, which, it turns out, is how our skin communicates with us!

References

1. Arıcan O. Kasintinin patofizyolojisi, klinigi ve tedavisi Turkderm 2005;39(2):88-97
2. Jonston G, Sladden M. 2005 Scabies: diagnosis and treatment BMJ;17;331(7517):619-22
3. Guyton AC, Hall JE. Tıbbi Fizyoloji 10. Baski 2001.p815-42
4. Schmelz M. Itch and pain. Neurosci Biobehav Rev 2010;34(2):171-6
5. Arck P, Raus R. From the Brain-skin connection. Neuroimmunomodulation 2006;13(5-6)347-56
6. Metz M, Stander S. Chronic pruritus pathogenesis clinical aspects and treatment. J Eur Acad Dermatol Veneral 2010;24(11)1249-60
7. Metz M, Grundman S, Stander S. Pruritus: an overview of current concepts. Vet Dermatol 2011;22(2):121-31
8. Chen ZF et all. Descending control of itching transmission by Serotonergic System via 5-HT1A-facilitated GRP-GRPR signaling. Neuron Vol.84(4) Nov.19-2014

9. Chan YH et all. Brain’s Reward Circuits Mediate Itch Relief. A functional MRI Study of Active Scratching. Dec. 2013

“There are numerous perfect mechanisms put to work by our Creator in a fashion that is impossible for us to know; it is equally impossible for us to control each of them.”

“This body is mine! Thus, I have a right to use it as I like!”

How do we own our body? How much of it belongs to us? Can we still stand behind the phrase “this body is mine!” when we explain “scientifically” that it is not? To what extent does that statement meet the truth?

First paragraphs of human biology textbooks strongly mention the phenomenon that the sustenance of life takes place outside our will. Does our first creation in our mother’s womb, when we become existent out of nowhere, happen by our will? Do we have a say in the creation of our body, which is the dress of our soul? Of course we don’t. Even our senses, which are involved in eating and drinking, exist outside of our will. The feeling of hunger, for instance, does not come forth from our control; it is dependent on the emptiness of the stomach, and low blood sugar. Hunger is not only a sense of alarm or warning, but also a feeling that forces one to eat; it disappears when one is full. If it was only a sense of alarm, one could get away with it. This situation shows that the human is not a machine composed of flesh only. If we refuse to respond to this feeling of hunger, it may eventually lead to serious, even fatal, consequences, such as patients suffering from Anorexia nervosa, a severe psychological disorder that can lead to self starvation.

If there were no such thing as hunger or appetite, humans would not be interested in working. The feeling of hunger is a remembrance to the One who provides. As a matter of fact, all our emotions are temporary belongings that provide for the sustenance of life, and for the continuation of generations. Sexual desires are provided so that we can have families and can continue the human race; an appetite for food is given so that we can maintain our lives, and the sense of cold is given so that we dress.

In our village, one of our neighbors suffered from a stroke. All of the senses of pain, hot or cold, and touch disappeared from his legs. A pathological sense urged the patient to ask care takers to warm the stroked leg. Upon the patient’s strong request, care takers tried to warm the underside of the foot with a hot iron over a piece of cloth. As a result, the patient suffered severe foot burns all the way to the bone, since neither the patient nor the care takers noticed the damage. The nerve endings embedded in our skin are in charge of sensing hot or cold; and nerves that are buried deep in our legs and arms are tasked with relaying those senses to our brain.

Despite feelings of cold or excess heat being connected to certain areas of the brain and nerve cells, these senses are not completely delivered to brain. That is to say that we are not simply machines made out of elements found in the earth. We do have emotions and a soul in charge of controlling those emotions, and a spiritual world connected to it. It is such that even senses of hot and cold do not belong to us and we cannot even generate or control them.

We cannot start our body just like we start a washing machine. We do not have a button to restart our heart in case it stops. How does a heart work? Have we ever thought about the number of nerves employed in sympathetic and parasympathetic autonomous nerve networks that make the heart work? All of the muscle cells of the heart contract with perfect timing. Do you know that special channels called “gap junctions” in between neighbor muscle cells are put to work wondrously in order to let electric signals pass from one cell to another? If millions of muscle cells in a heart did not have to work like that, how could all our cells get their nourishment, necessary substances, and oxygen in time? All of these processes happen outside our will.

How many red blood cells or white blood cells do you have, and how are they working? When the hemoglobin molecule reaches cells, it releases the oxygen molecule that is bound in lungs. Does the hemoglobin do this act of binding and releasing by its own discretion? Red blood cells get accelerated with proper speed so that cells get their nourishment on time. Is this something we do on our own? Our body is protected from diseases as white blood cells recognize and attack foreign microorganisms and substances. How can a white blood cell separate normal cells from harmful bacteria? There are numerous perfect mechanisms put to work by our Creator in a fashion that is impossible for us to know; it is equally impossible for us to control each of them. We do profit-loss calculations in every business of ours. Our body employs a great principle of economy; do we know how that is put to life or who makes that work?

Neurons, axons, dendrites, synapses, and neuro-transmitters exist and function in amazing numbers in our brains. Countless connections between neurons, and electric currents through synapses, happen without us even noticing them. How do neurotransmitters only bind with their own receptors and open ion channels? How does this relay of information occur in our brain when Na and Ca ions, existing in soil, rocks, and salt – which we use as a condiment – pass through these electrically controlled ion channels? Even if we know about these intricate works, it is still not up to our will to enable or control them.

How do nerve networks function? How many types of neuron circuitries exist, and how do they work? How does membrane potential form in nerve and muscle cells? How is action potential generated? When we touch a substance, which nerve tracks are utilized to transport the information? Do we have the option to pull the plug of pain and feel free of it? If this machine-like body belonged to us, then we could control and regulate it.

When we are purchasing a computer, we get the hardware according to our budget. We ask and order for the processing speed, memory, and the capacity of a computer to meet our needs. Do we get to arrange the capacity of our brain that we think we own?

Do we know that more than 75% of chewing is a reflex and happens outside our control and will? How good is it that we realize that only one of the three phases of swallowing is actually under our control and the rest of the process happens by our reflexes during eating and drinking? If swallowing was to be in our control, it would be highly likely that pieces of food and fluid droplets would easily choke our lungs and might cause death. How do our stomach and intestines work? At what speeds do secretions and movements take place? The content and amount of oral, gastro-intestinal, and pancreatic secretions are regulated according to the amount and type of food we intake. These regulations continue through our lifespan without any cessation.

Are we able to stop our heart beat when we are just a baby in our mother’s womb even for a minute? How does our heart work? How much blood is pumped in a minute? Approximately how long after the conception of egg and sperm does the heart start to beat: weeks, days? Do we know that our heart starts beating when we are as small as a tiny piece of flesh around week four?

How can we assert that we control our body, even when, to this day, scientists do not have a solid comprehension other than some assumptions of the rhythmic continuation of respiration during sleep or coma?

Since we own this heart and lungs, therefore can we manage to die whenever we want to stop them? Never!

We can conclude that the assertion of “this body is ours” is a deceptive, misleading perception. This body is given to us as a temporary belonging. It is very clear scientifically that all of the works, acts, and wondrous arts of the body do not belong to us, but to the One who created them. Our responsibility is to keep that in mind and be thankful for all the bountiful blessings.

Omer Arifagaoglu is a professor of medicine in Turkey.

(continued from the previous issue)

Using the distinct groves and folds on the hemispheres as a guideline, a map drawn on the cortex identifies focal points, where the various senses are concentrated, and activities in particular regions. Each of these different colored schematic centers has a specific name and performs specific functions. For example, the region above the neck at the back of the head (occipital lobe) is the field of sight; the sections that coincide with the temporal region is the field of hearing; immediately in front of this, on the left, is (generally) the field of speech; in the forehead region (frontal lobe), on the anterior wall of the middle canal is the initial center of planning of movement; on the top section of the front region is the field of complex movement; immediately behind here, in the middle-side region, is the field of simple movement; the area behind this, next to the hearing field and extending upwards, is defined as the touch receptive field. However, these areas are not confined, but rather spread out, and have a very complex connection network. The duty of the adjoining areas of these regions is to display and decipher the meaning of the signals received from the nerves. As the received signals regenerate past experiences and memories, the object or event sending the signal is recognized. To perform voluntary complex movements, the plan of movement must initially be defined in the mind and then the combination of this plan is conveyed through my nerve fibers to the movement regions. As complicated activities in humans, such as talking, and activities that involve the sensory integration mechanisms are miracles in themselves, it is quite astonishing that certain people claim that humans evolved from apes, later learning how to speak. The spinal cord (medulla spinalis) that extends from the skull in the form of a long cord, is the central nervous system sending signals to the body regions under the neck. The grey matter of the brain is located on the surface, while the white matter lies beneath the cortex; however with the spine, the butterfly shaped grey matter is inside, and the white matter on the surface covers the grey matter. In this central nervous system, all of the sensual messages that are received from the entire peripheral system, in particular from your skin and muscle, are immediately connected with the synapses or connections of the movement cells, and thus a spinal reflex is produced. As a section of the connecting cells (synapses) responds with a reflex, the other section transmits the signal to me to determine the appropriate voluntary response. For instance, if you tread on a nail, as the nail goes into the foot, a signal is transmitted by the sensor fibers to the spine, and to avoid a loss of time, the spine immediately signals the movement nerves before me, and a command is transmitted to your muscle you to raise your foot. And after your foot is saved by instant reflex, you begin to perform the other conscious activities, for example; you avoid putting weight on the foot, and bandage the wound if it is bleeding.

31 pairs of nerves (right and left) emerge from the spinal cord; 12 pairs from the brain area lay beneath the skull. These are all nerves that emerge from the central nervous system, and are distributed to various organs of the peripheral nervous system. All of the head nerves that emerge from the skull, with the exception of the tenth nerve, called the vagus nerve, control activities related to movement and senses in the head and neck region. Each of the 31 nerves exit from a space in the side of the vertebrae, and each of these nerves has two roots, an afferent nerve (sensual nerve), and an efferent nerve (movement nerve). These roots join immediately outside the spinal cord, and form the cords that carry the sensual and movement nerve fibers. These nerve cords are distributed in a plan and system that is specific for each organ. For example, the receptor sensor cells that sense a needle pricking your finger transmits this signal to the spinal cord through the receptor cell of the arm. The responsive reflex of pulling the hand away, a reflex from the spinal cord, is sent to the arm and hand muscles, and you pull your hand away. This is an example of a simple reflex. The movement nerve cells of the peripheral nervous system are divided into two, the somatic nervous system, which is distributed to the skeletal muscles, and the autonomic nervous system, which is distributed to the inner organs. Whilst the majority of the activities of the somatic systems occur voluntarily at the conscious level, the activity of autonomic systems is mainly involuntarily, or below the level of consciousness. The autonomic nervous system controls the smooth muscles of the heart, glands, blood vessels, respiration, digestion, urination and reproduction systems without our even realizing it. Dear Peter! Could you manage to do all this if you were in control? Your self control can only intervene until you place food in your mouth. Then the digestive secretions, the stomach and bowel activity, and the excretion of waste are all conducted automatically, totally beyond your control. Your breathing continues while you sleep, your kidneys never cease to function, your heart never rests, and your liver never relaxes while you sleep; your pancreas continues to produce insulin. All of your internal organs and blood vessels continue to function with the smooth muscles whenever necessary. And all this activity is conducted without you even being aware of it. If you tried to do all this, you would become exhausted within five minutes, lose interest and become unable to cope.

The nerve cords of the autonomic nervous system are divided into two, the sympathetic and the parasympathetic. These two systems have been created in such a way that they respond in opposition to one another, and every organ is provided with a stem from both. Therefore, no organ of the body is left uncontrolled. Whilst one signals and encourages the organ to function quicker and generate more outcomes, the other acts to the contrary, sending signals that encourage the organ to slow down. In which case, with these two contrasting signals, the organ protects its optimal functioning tempo according to the situation and conditions. The sympathetic system generally responds in cases of stress and shock, preparing the body for the effects of such situations. For example, an increase in your blood pressure, blood-sugar level, and perspiration, the dilation of your pupils, and an increase in the flow of blood in your muscles all occur from the effect of the sympathetic fibers. The parasympathetic system sends adverse signals, such as reducing blood pressure and so on, so that the organs return to their neutral state and continue their normal functions.

From the very beginning I have described many of my sections and signals, but I have not yet told you about my key to life, my nerve cells, and how my nerve cells function. 30 billion cells, known as neurons, are the actual units that function in every part of my system. A neuron has a cell body and emerging filaments like tree branches. The single thicker filament like the tree trunk is called the axon, and the thinner filaments that emerge in larger quantities like tree branches are called dentrites. The nerve signals advance from the axon to the dentrite in the form of an electrical pulse. In the space between the connection point (synapses) of a nerve cell axon and the other cells, the dentrite, a chemical substance, called the neurotransmitter, is released. When these substances, in the form of neuropeptides, amino acids, acetylcholines, and monomines, reach the wall of the opposite cells, it an electrical pulse is immediately ignited in the dendrite. Just like a row dominos, falling down one after the other, or football fans performing the Mexican wave, a wave-like effect is generated and these electrical messages are fired with great speed from one end of the cell to the other, advancing in the form of tiny electrical pulses to be transmitted to neighboring cells. While a cell at rest has a potential of 70m V, the action potential of up to +30 – +40m V can transmit all types of information. Every cell can transmit up to 1,000 signals per second.

While you still do not recognize the true value of what you call the memory, which records hundreds of experiences every day, various theories are presented regarding how this bank which stores information in your brain actually functions. But we all know that the answer to this question lies within the millions of neurons that constitute me. Just as all of the senses, thoughts and actions occur from electrical and chemical signals that are transmitted from one cell to another they are presumably recorded in the same way, that is, with electrical and chemical signals.

It is difficult to define a precise center for the boundaries of the memories in me; memory could be interconnected with all of my regions. The storing of certain memories, some voices, visions, smells, or dreams, or the sense of resentment, anger or joy, is all carried out in different forms. You could not even begin to imagine the greatness of the memory storage! I have two types of memory, one short and one-long term. In my short term memory, I can store up to between seven and nine different things at any one time. Nothing remains in my short-term memory for more than a few minutes. Everything that you remember after this is stored in my long-term memory. In my long-term memory things can remain for days, months or even years. Everything you know and learn is stored in your long-term memory. By the time you are eight years old, the information in your memory is enough to fill one million pages. However, this is a mere drop in the ocean; the long-term memory is so vast that it can never become full. Even when you reach a hundred, I will have the capacity to store new information, so never assume that you are overloading a child’s mind and never deprive them of education…Some presumptuous people say; “Never force a child to memorize at a young age, it will affect the brain.” Do not believe them! The learning of foreign languages, the Qur’an and religious education is recorded in my memory by electric pulses and this is so much easier and healthier in the early stages of life. In fact, such activities at a young age can even strengthen the memory. The event called ‘recollection’ is the repeat of the electric pulse codes that are recorded at the actual time of an event. Occasionally you try to remember a person’s name, and although the name is on the tip of your tongue, you just cannot remember. You struggle and eventually give up. Then suddenly, two days later the name comes to your mind. You are quite puzzled and of course pleased that you have remembered, but have you ever wondered how this happens? As you try to remember, you control each of my nerve cells individually, because you are not sure where you placed the files that bear this information. But you are unable to find which section of the millions of cells bears the information. As you have not used this information often, or because you did not consider it to be important, you did not register it in a particular place. But you would never forget your father’s name, as it is important to you and use it often, so the file is in front of you constantly. Well, you get frustrated at not being able to remember and stop searching; however, what you call the subconscious is in fact a much more mysterious mechanism. It begins to search without you being aware of it. Then to your surprise it produces the file two days later. The subconscious is a very mysterious place, it affects everything about you. Only the most sincere feelings are recorded in the subconscious; no veil, no hypocrisy, only actual thoughts are recorded. And also events that deeply affect you, the sad or bad memories you experience, and of course sins…The subconscious is what causes the sense of guilt or an inferiority complex; this is reflected in much of your behavior. But problems like guilt or an inferiority complex are something we can change; it all depends on you. If you are a person who has self-control, you perform good, favorable deeds, and are continuously patient; thus you can eventually renew the contaminated sections of your subconscious so that it will not upset you anymore. Indeed, this is the reason why, of all the creatures on earth, only humans were blessed with the sense of remorse and faith. If you suppress feelings of guilt and sin in the subconscious, the autonomic system affects the organs without you even realizing it; the thalamus, hypothalamus, or the pituitary gland (hypophsis), which are small in size, but bear a great responsibility; eventually this disturbs the balance of the whole body and you become ill. Although this may not be an organic complaint at first, due to psychosomatic symptoms which are caused by suppressing your subconscious, over time this will affect the functions of one of your organs and you become ill. Of course the exact opposite is also possible, with inspiration, pleasant thoughts and good actions the positive signals transmitted to the affected organ may possibly be the means to recovery.

Dear Peter! I have so many more facts and mysterious functions to describe to you, but unfortunately the pages here are not enough. Well, I suppose I must stop somewhere. I really wanted to talk to you about a number of different things, like dreams, mental illnesses such as Parkinson’s, Alzheimer’s, strokes, sleep, hypnosis, and the damage caused by drugs. However, each of these subjects is so vast, and many of them have already been explained in previous issues, so for now I will leave it to others to describe these subjects to you, and say my last words…

Dear Peter!… While your hand is writing and reading these words, or explaining what you have read to your friends, or learning all this information and passing it through the filter of thought, you are constantly using my nerves and my systems. There is not a single moment where I am not informed of events that occur in your body. Who knows just how much of the mysteries in me you will use in order to rise to the peak of accomplishment with the blessings that have been bestowed upon you by the Creator. Even the greatest computers made by human beings are mere toys compared to me. Nevertheless, the knowledge of engineers and craftsmen which design, plan, and place every piece into these computers with total accuracy is only possible because of me. Presumably you are not denying those who designed, constructed, and made the computer operate, are you? In which case you should thank God, the One who created me, an organ whose capacity exceeds that of thousands of computers, with His eternal power and wisdom; always remember to use me in good, blessed, and honest actions!…May God protect you!…

Irfan Yilmaz is a professor of biology at Dokuz Eylul University, Izmir. 

Finally, I have come to say goodbye to you. As you probably know, there is a saying “Leave the best till last.” I am the greatest of all the organs and systems that have described themselves to you so far. I am an integrative system that forms a chain between every organ in your body. Just as your veins are spread out to carry nutrients and oxygen to every part of your body, I also embrace your entire system like a network, without leaving the tiniest space; I am informed of everything that goes on inside your body. Even if a tiny insect settles on your arm, you sense it immediately. I make you aware of a tiny drop of sweat on your body. I induce pain in suitable measures to inform you of any illnesses in your inner organs. In fact, I not only inform you, I also warn you to seek help.

However, it is hard for me to describe myself. When you hear the words “nervous system,” what comes to mind is a cluster of cells called neurons. But this is a great mass of cells, and we should always remember that we are referring to the most complex matter in all of creation. The very important main nervous systems, which are very close to one another, are the huge masses positioned beneath the skull, the extensions of my system and secondary nervous system; this latter is spread out through various regions of the body. It would take up too much of your time to describe each region and branch of my system individually to you each month, but in this way I could prove what a perfect and incredible duty each of them performs within your body. However, I will try to explain the subject briefly to avoid boring you. Nevertheless, please forgive me if I ramble on too much; we are describing the most excellent organ created by God so it is inevitable that there will be some complicated matters that need clarification.

Instead of allowing each of my sections to describe themselves to you individually, I will speak on their behalf as the “brain.” It may be easier for you to understand the system if we divide it into two. One of them is me and the nervous system which I lead; we can briefly describe this as the thalamus, hypothalamus, cerebellum, the medulla, and the spine. The other part is the peripheral nervous system, which emerges from the central nervous system and is distributed, rather like fiber optic telephone cables, throughout the entire body. In addition to me, the brain, and my two large cerebral hemispheres, there is another smaller section, which is known as the brain stem. The brain and its cerebral hemispheres and the sections of the brain stem which are protected beneath the skull (the cerebellum, medulla, thalamus, and hypothalamus) are very important. The spinal cord, which is also a part of the central nervous system, however is not in the skull, but positioned within the vertebrae that constitute the spine. Due to its connection with the central nervous system, any damage to the spinal cord can endanger life.

Although damage to regions of the body where the nerves are distributed from the central nervous system may cause paralysis, or functional disorder for the specific organ, such an incident is not life threatening.

If you recall, when the heart and circulation system described themselves they boasted – indeed the veins also seemed to brag a bit when they stated that they measured 75,000 miles (long enough to go around the world almost three times). But the nerves are approximately 477,000 miles, long enough to stretch from the earth to the moon, and back again… the nerves which are distributed throughout the various parts of your body measure 250,000 miles, and the total length of the central nervous system is 228,000 miles. Almost 200,000 signals pass through just one cell at a time, which means that every moment thousands of signals pass through millions of my cells all throughout your body, and flow from the central nervous system to the whole body and then back to the central nervous system. There are about 30 billion cells in my system. 10 billion of these cells are in the cortex, 10 billion in the cerebellum, and the remainder forms the structure of the nerves and other sections. As a comparison, a fly’s brain contains 100 thousand cells, and a rat’s brain has 10 million cells. The total number of connections and contact points (synapses) that my 30 billion cells use to send and receive signals is 100 trillion. The number of combinations that these connections can establish to send signals to one another is greater than the number of atoms in the universe. At the beginning of a thinking process, the number of cells activated is between 10 and 100 million, and according to the depth and intensity of the activity, these figures can increase to astounding numbers. Every second 4 billion signals are exchanged between the left and right hemispheres. When you were an embryo, just a few weeks old, I consisted of 92% water. When you were first born, the ratio of water was 90%. And when you were fully developed, the water ratio remains at 77%. Peter! Can you imagine, a heap of mass consisting of 77% water, the remainder made up of various element. Our Lord, the bearer of eternal power places me in you, in the head of the most honorable creation, and with me you form civilizations; you invent and discover. And even more important, with my mediation you have the ability to contemplate and reach your Creator. What we are learning about here is how with me you are able to recognize the wisdom of the entire universe. The electric signals of the various sense organs, such as the eyes, ears, nose, tongue and skin, all of which have previously described themselves, are transmitted by the receptive cells on various wavelengths; these are then conveyed to you in the form of sight, noise, smell and taste. In fact I am inducing you to write these words at this very moment. The evaluation of everything you do passes through me, but you are not even aware of it. When you walk, eat, talk, speak or sleep, the information I receive from every part of your body is reviewed and responded to in a suitable manner. Dear Peter! Could a single nucleus of a single one of my cells possibly position itself alone?

The Lord has created me so magnificently that you are still only aware of a very few of my mysteries. Each of the sections that I mentioned above has a distinct and important vital function. On their behalf, I will briefly explain their duties: The cerebellum is the nerve center from which the harmony of balance and muscle movement is controlled. As this section of me has no sense of perception, it is impossible to voluntarily change the functions of this region. The pyramid shaped medulla oblongata, which connects the spinal cord to the midbrain and the pons; the latter constitutes the other end of the brainstem through a hole in the back of the skull in the form of the spinal cord and enters into the vertebral column. Here, there are many nerve centers which regulate autonomic nervous system activity, such as the heart rate, breathing, and digestion process. This is also the center from which the reflexes are controlled, the body’s inner environment is regulated, and this center, working with the cerebellum also controls movement and coordinates signals received from the nerves of inner organs. Moreover, activities such as excitement and sleep are also controlled here in collaboration with the thalamus.

The thalamus lies between the brainstem and the hemispheres of the brain, performing a function rather like a junction or relay station. This section gathers all the signals sent by the sense receptors, except for those from the olfactory (smell) receptors, and conveys these signals to the cortex reflecting the information; there is also a role played in consciously identifying sensations such as pain, touch and noise. There is also a role played in the sensory changes that occur with the perception of senses in our consciousness and awareness, as well as in the regulation of sleep and paying attention. The hypothalamus, which is located below the thalamus, is an important center that controls sexual senses; the sensations of pain, pleasure, hunger, and thirst, as well as blood pressure, temperature and other functions of the inner organs. It also performs the important duty of regulating hormone release. The nerve fibers that enter this center, which is the location of a very complex network of nerves coming from the olfactory bulb, thalamus, and the frontal lobe, reach the autonomic nervous system, the reticular formation in the stem section, and the posterior lobe behind the pituitary gland (hypophysis). The pituitary gland, one of the most important systems that earlier described itself in the endocrine system, produces hormones that stimulate secretion in the anterior section, as well as the oxytocin and antidiuretic hormones which are stored and released from the posterior pituitary.

On the base of the deep grove that separates the two hemispheres of the large brain there is a callus-like body; this is a bundle of axon (nerves) called the corpus callosum which connects the two hemispheres. Because the nerve fibers cross and change direction in the medulla, the left side of the brain controls your right side, and the right controls your left. Although my two hemispheres may look like a reflection of one another, there are some variations in their duties; for example, the left hemisphere controls speech, but the section which controls the perception of location is in the right hemisphere. Whilst you use the left hemisphere for duties that must be performed in a specific order (activities such as adding and subtracting or buttoning a shirt), you use the right hemisphere in thinking with images (for example, mapping the route from your home to the market). If the callus substance that connects my two hemispheres did not exist, there would be no communication between the two, therefore, you could read the word “fish,” but you would not be able to picture the image of a fish in your mind without the right hemisphere to achieve this.

The brain, the grey-colored mass of folds and grooves that covers the top of my anatomic hemispheres, the region where the main stems of my cells are found, is called the cortex or grey matter; the lighter colored matter that lies beneath this, the region where the axons (stems of neurons) are found, is called the white matter. My cortex region, which is composed of six layers of cells, is the center where the sensory signals are received and analyzed and where voluntary muscle movement is controlled, while also being the center of activities, such as learning, reasoning, and remembering. My two hemispheres, the focal point of conscious activity and thought that forms the large brain, constitute 85% of the whole brain. When you were first born I weighed 400 grams, but I grew very quickly, and by the time you were a year old I weighed 800 grams. When you were four years old, I weighed 1,200 gr. However, my growth began to slow down after the age of seven, and when you reach twenty, I will weigh approximately 1,379–1,434 grams. When you begin to pass your first youth, my weight begins to decrease every year by 1 gram, so when you reach seventy-five, I would have shrunk in comparison to when you were twenty. The reason for this decrease in weight is that approximate 50,000 neurons die, or cease to function daily, after you reach the age of twenty. The body cells of the cartilage, bone, skin, ligaments and the liver divide, regenerate and increase in number; however, the nerve cells that are part of me continue to increase until they reach the figure set out for you when you were formed in your mother’s womb; they then lose the ability to segregate. So if there is any damage, relative functions fail because the cells in that region have died. Then the question arises: As there is no increase in the numbers of cells, how does the weight continue to increase until the age of twenty? Well, there is not an increase in the numbers of cells; rather, there is an increase in the number and growth of connections between the cells and this is how my weight increases. Of course, nutrients are added to build and stimulate these connections. Subsequently, with age these connections begin to decrease. With ever experience you have, all the things that you learn or see during your youth these connections increase, and in turn this increases my capacity for thought and reasoning. If you continue to activate your brain by reading, writing and other social activities in old age, these connections continue to increase. Even if there is a decrease in my cells, you are able to continue your usual activities without losing any functions of the brain. But as soon as you say that is enough, it is time for a rest, my cells begin to withdraw their connections immediately, and in time you will certainly see the difference in my capacity. If the cells in my central nervous system are injured or damaged, they cannot repair themselves. However, if the cell bodies of my cells in the peripheral nervous system are not damaged the stems are repairable.

Thanks to this special feature if a severed arm, leg or finger can be carefully replaced with microsurgery, the nerves can repair themselves, and the limb will continue its normal functions. The visible cause of this characteristic is found in the nerves of the arms and legs, but not in the brain or spine, is the casing that surrounds this bundle of nerves that transmits signals for the cells to grow. Even with the greatest of techniques, no surgeon could sew the severed nerve fibers. However, thanks to the nerve casing that holds these fibers together (like the plastic that covers the electric cable, consisting of thin wires) the severed limb can be replanted. Then with guidance from this outer casing, each of the hundreds of fibers found inside grow 1 mm every day, and in a period of between 1 month and a year, they will begin to function again.

Irfan Yilmaz is a professor of biology at Dokuz Eylul University, Izmir. 

Adam forgot, so did his children.

How does our brain store information? How is it possible to make learning faster and easier? Is there any way not to forget what we have learned and to remember things more easily? Of what importance is the fact that information is never deleted from our memory, even if we have forgotten it? These are among many of the questions for which answers have been sought over the years.

Memory is one of the functions of the brain and it is defined as the ability to preserve acquired information consciously and relate it to the past. It is not just a certain portion of the brain, but rather the entire organ that functions in storing, processing, and retrieving external and internal signals. Signals that build up our memory are what we usually perceive through our five senses. When we burn our hand, or see or experience a traffic accident , when we are given a compliment and many other events are all examples of external signals, whereas internal signals are related to our nervous system or imagination. The pain one feels during a heart attack, the anxiety of a cold sweat, or a beautiful daydream are all stored in our memory too. We may or may not remember them. There is no deletion; it is simply that we do not remember. Forgetting is a state that is encoded in our makeup with differing degrees, depending on the kind of life the person has experienced. Age, gender, stress, habits, and illnesses all have varying roles in forgetting.

Short-term memory

Short-term memory refers to saving and remembering what we have learned a few seconds or minutes ago; the prefrontal brain is the location for this temporary processing. Signals are kept in this portion of the brain for a few seconds and then conveyed to the back stage (as in the transfer of data from the cache memory to the main memory in computers). We tend to quickly forget those things on which we have not spent a long time or to which we have not assigned great importance, even though we can understand them. Imagine how unbearable our life would be if we were to store in our memories and remember things in infinite detail like the color of the wall we are facing, the variety of the objects around us and their qualities, the air we breathe in and out, or every beat of our heart. The signals that come to our brain within a certain time frame are filtered according to our needs and their significance and limitations are applied depending on their qualities and quantities.

There is no consolidation processing for short term memory. Second or minutes after signals are received they are retrieved in accordance with what we need; if they are insignificant for us, they are forgotten in the same amount of time. The information that is significant for the person is consolidated in the hippocampus and reserved in mid and long-term memory units.

Mid and long term memory

After being processed in the sub-cortex (limbic system) of the brain, signals are saved. Depending on their level of urgency, the meaning they stand for, and their emotional effect, signals are saved in either the mid or long term memory. Pain, joy, pleasure, and fear are states that solidify memory traces. A heart attack, the infliction of wounds and bruises or humiliation, accidents, visits from a loved one-these are all examples of events that are easily remembered. However, a lasting record is almost impossible to attain if the subject is something that has been forced (like a student studying for higher marks) or if the subject does not appeal at all. Consolidation is necessary to make a short term memory a lasting one. However, if a student is curious about the subject and enjoys what he or she is learning, then long term memory is possible without too much effort in consolidation. Forced consolidation (e.g. a student’s orientation to attain higher marks) requires a longer period. The information is consolidated more easily when a person is in a sound and alert state of mind.

Storage in the long-term memory does not occur immediately after something has been learned or experienced. For this storage to be possible at least an hour needs to pass to synthesize the memory proteins that are responsible for recording. If electric shock is applied to a person’s brain immediately after an unforgettable event, they will not be able to remember the event. But if the electric shock is applied an hour later, the memory remains.

Once stored in long-term memory, information can be retrieved, even after months or years. When new information is obtained older information is called up and they are saved with a new pattern of storage, with the newcomers being related with the ones that have already been stored; it is in this way that long term memory is generated.

It has been argued that RNA has a role in storing old information. In experiments, guinea pigs were taught information through repeated practice which is stored in their long term memory. The brains of these animals were later minced up and fed to other animals. It was observed that those animals which had been fed the brains learned faster and more easily than other animals that had been fed on a diet that did not include the brains. This shows us that information encoded in the memory is not lost; rather it is transferred with the help of certain molecules. It is also known that DNA is related to genetic memory.

It has been found that people with good memories have a greater number of nerve cells and channels of transfer in the memory-related zones of their brains (cortex, corpus callosum, hippocampus, thalamus, hypothalamus, limbic system, amygdale, temporal lobe, and prefrontal cortex), while there are less cells in other zones of the brain. Nerve cells are stimulated while signals are stored in one’s memory. Even if a person has a weak memory, activities like reading, memorization, or other engagements that improve love, happiness, and peace of mind may help long-term memory.

Forgetfulness

It is important to find out whether forgetfulness occurs because of an illness or something else. Age is one major factor. Forgetfulness in an aging person is proportionate to the number of the loss of cells.

Stress, dealing with multiple things all at once, or occupying oneself with things that are of no benefit, that is, creating a pollution of information, all affect short term memory and may cause forgetfulness.

Forgetfulness due to damage or illness

If the nerve cells of the lower occipital lobe of the brain are damaged, old information cannot be retrieved. Likewise, in case of damage to the nerve cells that are found in the temporal lobes on the sides of the brain, or due to an insufficient intake of B3 and B12 vitamins, cerebral hemorrhage or an embolism in the veins of the memory zones forgetfulness may occur.

Patients with Alzheimer indicate short term memory loss. They tend to forget visitors’ names, daily events, or the doctor’s advice.

Chronic alcohol abuse may cause damage in the hippocampus and thus in the ability to encode information.

Electroshock may also delete recent information that has been recorded in the short-term memory. Thyroid failure, Parkinson’s, hydrocephaly, schizophrenia, brain tumors, and epilepsy may also cause forgetfulness.

Some advice

Spiritual teachings and religious services have many positive aspects in our lives in addition to being our duties for expressing our servanthood to God Almighty. In Islam, for instance, principles like “enjoining good and forbidding evil,” praying at night, a brief afternoon nap, staying away from what is forbidden, reading and/or memorizing the Qur’an, and other activities may provide some protection against forgetfulness.

It is also claimed that keeping oneself busy with things that are considered morally improper, not least things that are sexually provocative in an illegitimate way, may damage neurons that are operative in memory. In order to be less affected by forgetfulness in our advanced years, it can be helpful to read spiritually and intellectually useful material, to learn and memorize new words and concepts, to keep oneself in good moral condition by engaging in charity work and helping others, and to maintain good sleep and a healthy diet

On the other hand, thinking a bit more wisely, to be able to forget (not forgetfulness) also has many benefits. Our nervous system is relaxed by forgetting, otherwise it might collapse. Forgetting old informa¬tion could well open up room for new information, although this does not mean that the information is deleted from memory; it is retrieved when needed. But, if forgetting reaches a level that is above medically ex¬pected averages, then medical help should be sought.

There are incidents of patients who are suffering from dementia and Alzheimer regaining their memory after electroshock therapy. Perhaps this is evidence that we will remember and testify for all our actions when we will have to account for them.

The discipline in which medicine and engineering truly meet and face new challenges is the field of “biomedical engineering,” an emerging discipline that is only a few decades old. In each sub-specialty of biomedical engineering, researchers study the human body, develop new materials and structures using engineering sciences, either as a treatment method for disease (e.g. artificial bone implants, artificial blood, vascular stents, cardiac valves, etc.) or to diagnose them (e.g. imaging methods and other diagnostic instruments in hospitals). Biomedical engineers face the incredible challenge of developing materials and devices that are compatible with biological systems and capable of working inside the human body to substitute bodily functions. Needless to say, the extreme complexity of the human body makes it impossible to mimic the original system or function of the organs in any way. However, even a poor replacement part or a functional improvement provides great benefit to the patients.

One of the most complex systems of the human body is the nervous system, which consists of the central area (the brain and the spinal cord) and the peripheral parts. The branch of biomedical engineering that deals with the nervous system is “neural engineering.” In this article, we will touch upon a specific subject in the broader area of neural engineering, that is, “neural prosthetics.”1 As the name implies, neural prosthetics is an area where engineering knowledge is utilized to treat neural disorders.

The building blocks of the nervous system are called “neurons.” Neurons generate electric pulses to communicate with each other. The fact that these electric pulses can be elicited by artificial means, i.e. by applying small electric currents to the neurons externally, forms the very foundation of the field of neural prosthetics. Neural engineers can input information into the nervous system by taking advantage of this phenomenon, called “neural stimulation.” Likewise, the information content of neuronal activity can be deciphered by recording the electrical pulses from the neurons and interpreting them according to neuronal function. This two way traffic, monitoring and controlling the neural activity, allows researchers in this field to develop methods of treatment for some sensory, motor, and psychological disorders.

Some of the most successful neural prosthetic applications have been in deep brain stimulation in Parkinson’s disease,

cochlear prosthesis in hearing impairment, bladder emptying and respiration in spinal cord injury, and vagus nerve (10th cranial nerve) stimulation in epilepsy and psychological depression. These are neural prostheses that are readily available as a treatment method for the given ailments. There is a whole host of others that are in the research and development phase. We will review a couple of examples.

In certain diseases of the inner ear hearing is lost as a result of damage to the hair cells inside the cochlea. In normal cochlea the sound information reaches these hair cells after traveling through the ear drum (tympanic membrane) and the structures of the middle ear, causing them to vibrate. This vibration of the hair cells is mechanically transported to the spiral ganglion cells that form the hearing (auditory) nerve. The hearing nerve carries the sound information to the brain in the form of electric pulses. The ganglion cells are healthy and functional even if the entire population of hair cells has been lost as a result of disease. Neural engineers take advantage of the fact that the spiral ganglion cells (which normally accept input from the hair cells) can be electrically stimulated, thus mimicking the function of the hair cells and producing the sensation of sound.2 During a simple surgical operation, the surgeon inserts an electrode into the ear canal which spirals into the lumen of the cochlea so that the sites where the electric current emits from the electrode are adjacent to the spiral ganglion cells (Figure 1). To summarize the principle of the operation; the audio signals are captured by a microphone, processed, converted into electric pulses (A in Figure 1), and transmitted to the implant over a transmitting antenna (B in Figure 1), or headpiece, held in place by magnets. The implant (C in Figure 1) applies the signals to the ganglion cells in the cochlea through tiny electrodes (D in Figure 1). The hearing nerve (auditory nerve) carries the sound information to the brain, where it is “heard.”

Even though the human spiral ganglion has tens of thousands of nerve cells that provide a rich sense of hearing, the cochlear implant, using only six stimulation contacts, can produce auditory perception with sufficient fidelity to enable a deaf individual to use an ordinary telephone.3 Individuals with cochlear implants can also improve their hearing with practice. Thousands of patients have been implanted with cochlear prostheses to date, including children.

The second neural prosthesis application we will review is the retinal prosthesis, which, unlike the cochlear implants, is still in the research phase. Retinitis pigmentosa and age-related macular degeneration both lead to photoreceptor degeneration in the eye and result in a significant visual deficit or blindness.4 A growing body of research supports the feasibility of replacing the function of the photoreceptors with an electronic device. 5–7 A retinal prosthesis is analogous to the cochlear implant in many ways. In a healthy retina, the photoreceptors initiate a neural signal in response to light. In a retinal prosthesis, electrical pulses are utilized to initiate a neural response in the remaining cells of the retina, the bipolar and ganglion cells. It is hypothesized that the perception of shapes and images will be possible through pattern stimulation of the retina. Initial results are encouraging, but the quality of vision that can be attained with this approach is still a question to be answered. A conceptual retinal prosthesis system is shown in Figure 2. The system consists of an external unit coupled to an implanted stimulator with a wireless link. A video camera in the external unit captures an image and converts it to digital data. The implanted unit receives the signal, recovers power and data from the signal, and generates the stimulating current. The stimulus pattern is applied to the retina via the electrode array, which contains distinct electrodes that interface at many locations on the retinal surface. Recent implants in human subjects suggest the feasibility of this approach where individuals attain perception of bright dots in the visual field called ‘phosphenes.’ Furthermore, blind subjects are able to perceive edges when a few of these bright dots are lined up in their visual field.

Figure 3: A conceptual diagram of a Brain-Computer Interface for high level spinal cord injury or patients with ‘locked-in syndrome’ (adapted from Wolpaw et al., see note 9). The recorded neural activity from the motor cortex is processed and converted into command signals to control, for instance, a wheelchair, or to generate electrical signals to activate hand muscles for grasping an object.

Both cochlear and retinal implants are sensory prostheses, i.e. aids for sensory impairments. Another family of neural prostheses deals with motor impairments. Severe motor disability results from high level spinal cord injuries (quadriplegia) where most of the body is paralyzed, sparing only some face, neck, and shoulder muscles. Quadriplegic individuals are in extreme need of a means to control their environment; they need to be in control of their wheelchairs, bed, the room temperature, lights, TV, etc. Because of the level of paralysis it is impossible for them to generate any control signal, except perhaps by sipping or puffing on the end of a tube, which produces a very poor control signal. In the case of a ‘locked-in syndrome’ the condition of the patient is even more serious, with only some functions remaining in the facial muscles. The term ‘brain-computer interface’ has been coined to refer to attempts whereby the motor output of the brain is recorded and interpreted to generate the control signals needed by these patients (Figure 3,9). The ultimate objective of this research will be accomplished when the patients are able to control anything they need to control in their environment, including a computer. The brain-computer interfaces vary in the invasiveness of the approach. The least invasive methods utilize the electroencephalogram (EEG) signals recorded from the scalp. Unfortunately, the signal quality is poor and only ‘on/off’ type of command signals can be generated using this method. In the most invasive, yet most successful applications, an array of electrodes is implanted directly into the motor cortex of the brain at a depth of a couple of millimeters. The recorded signals contain volitional information as the patient makes intentions to move their arms or legs. These signals can be controlled by the patient, and they can in turn be used to control their environment. The current level of success in this type of BCI allows the user to have three dimensional control of a robot arm. This is of invaluable benefit to a quadriplegic individual.

Concluding Remarks: Reflections on Divine Wisdom

Even the subtlest parts of the nervous system are extremely complex. Just to name a few examples, from the highest centers in the brain down to the skeletal muscles in a descending order; the neural circuits of the short-term memory in the hippocampus, fine motor control circuits of the cerebellum, central pattern generators in the spinal cord, and even the control of skeletal muscles in graceful movements of the limbs are impossible to reproduce by artificial means. The Seal of Divine Design is clearly visible in these neural systems, as they are far more complex, far more compact, and far more functionally efficient than any system engineered by mankind. If anything, the growing experience in neurosciences teaches us that the vertebrate nervous system is full of wonders of engineering design. Therefore, it is a great blessing to be a student of both neurosciences and engineering disciplines. This bestows neural engineers with a unique perspective to understand the beauty embroidered into the human nervous system and contemplate on the Divine Wisdom. In spiritual terms, we may think of the human nervous system as a window opening to the works of Divine Wisdom, with manifestations of His Beautiful Names at the brightest level. It is an overwhelming joy to be able to open this window a crack, once in a while, and take a little peek.

References

1. Wise, K.D. ‘Silicon microsystems for neuroscience and neural prostheses,’ IEEE Engineering in Medicine and Biology Society Magazine, vol. 25, no. 5, pp. 22- 29, Sept.-Oct., 2005.
2. G.E. Loeb, ‘Cochlear prosthetics,’ Annu. Rev. Neurosci., vol. 13, pp. 357–371, 1990.
3. J. Helms, V. Weichbold, U. Baumann, H. von Specht, F. Schon, J. Muller, B. Esser, M. Ziese, I. Anderson, and P. D”Haese, ‘Analysis of ceiling effects occurring with speech recognition tests in adult cochlear-implanted patients,’ ORL J. Otorhinolaryngol Relat. Spec., vol. 66, no. 3, pp. 130–135, 2004.
4. E.L. Berson, ‘Retinitis pigmentosa. The friedenwald lecture,’ Invest Ophthalmol. Vis .Sci., vol. 34, no. 5, pp. 1659–1676, Apr. 1993.
5. E. Zrenner, ‘Will retinal implants restore vision?,’ Science, vol. 295, no. 5557, pp. 1022–1025, Feb. 2002.
6. J.F. Rizzo III, J. Wyatt, J. Lowenstein, S. Kelly, and D. Shire, ‘Perceptual efficacy of electrical stimulation of human retina with a microelectrode array during short term surgical trials,’ Invest. Ophthalmol. Vis. Sci., vol. 44, no. 12, pp. 5362–5369, 2003.
7. M.S. Humayun, J. Weiland, G. Fujii, R.J. Greenberg, R. Williamson , J. Little, B. Mech, V. Cimmarusti, G. van Boemel, G. Dagnelie, and E. de Juan, Jr., ‘Visual perception in a blind subject with a chronic microelectronic retinal prosthesis,’ Vision Res., vol. 43, no. 24, pp. 2573–2581, 2003.
8. Weiland, J.D. and Humayun, M.S., ‘A biomimetric retinal stimulation array,’ IEEE Engineering in Medicine and Biology Society Magazine, vol. 25, no. 5, pp. 14-21, Sept.-Oct., 2005.
9. Wolpaw J.R. et al., ‘Brain-computer interfaces for communication and control,’ Clinical Neurophysiolology, vol. 113(6), pp. 767-791, 2002.

Programs and documents on the computer are held in two areas: software and hardware. For scientists, one of many goals is to make the processors or chips, which are like the human brain that consists of nerves, much smaller, but still powerful enough to process many more calculations. There are many differences between the current chips and earlier ones. Chips which will be produced in the future will be smaller and probably process more calculations more quickly.

Programs, which can be seen as being the mechanical counterpart of the human mind, bring the above-mentioned improvements into daily life. New programs boost the capability of the computer in parallel with the capability of their chips. Without these programs, computers would be no more than ordinary electronic machines.

Developed technologies in fields like industry, communication, or the military bring us face to face with new developments and have made the computer an undeniable part of our lives. Mobile phones equipped with new features, medical machines which can easily make a large number of analyses and provide ease in diagnosis and treatment, robots that can operate with minimum error and have a low cost when used in production, and weapons that automatically focus on the target are all part of this progress.

With time, software and hi-tech sensors have enabled computers to communicate with people; there are now systems that are controlled by the voice, which are able to recognize a person from their iris or fingerprints, control systems which are carried out by touching a screen, etc. Such systems are operated with the help of special sensors or by some signals that carry messages from the person or the environment to the computer. The most important feature of these sensors is that the signals produced at the output are very weak and there are few differences between them. An ATM can recognize a particular person’s iris, thanks to the ability of its computer to compare the signals from the ATM’s iris scanner with previously recorded data. In this process, the computer uses the small differences that one person’s iris has to another’s. In this or similar systems, complicated programs are used, called “expert systems” or “artificial intelligence”. These programs imitate human senses, but they aim to operate with an even keener sensitivity and clearer criteria.

A question that is a subject of fiction comes to mind; “Will computers vie with or even fight with human beings?” In the mid-term, the rapid development of technology will create computers which can communicate with humans, which can understand them, and put forward ideas. A negative outcome of such a situation depends, once again, on man. Such a horrific situation could be the result of technology that can cause environmental disasters; this technology is almost identical to the one that we have described above. If we are able to establish an understanding of “civilization” which does not ignore human values for the sake of technological development, then such fears will be groundless.

Artificial Nervous Systems

As we all know, people have imitated nature in many of their inventions. In a way, artificial nervous systems imitate how a nerve cell learns and how it works. Fuzzy systems however imitate how the judgment of a human being works, rather than the nerve cells of the brain. In these systems people try to form a decision making criterion by assuming that there are endless grey tones between white and black or by assuming that there are infinite values between zero and one.

The purpose of the research on artificial nervous systems is to understand how the brain operates, then to make a system that imitates it and carries out the same operations. Artificial nervous systems are made of simple nerve cells which are bound in parallel, called process elements; these allow for real objects to be seen as if they were biological systems.

Here, the program that resembles the nerve cell operates in the same way as a nerve cell. The main part of a nerve cell is formed from the body, called a “soma”, an “axon” that is bound to the body and many “dendrites”. There are many “roots”, or synapses, on the dendrite of a cell which make contact with the dendrites of other cells. A nerve cell either transmits the electrical stimulus that comes through the axon to the other nerve cells through the synapse, or it does not transmit it, depending on whether or not the signal is over or below the threshold value. So a nerve works by itself, but its activity becomes meaningful when working as a part of a nervous system. It would be useful if we consider how the learning process occurs here. It is thought that the required data are stored in the memory center and this fact is taken as a model for some artificial nervous system software that has been successfully developed to date.

A nerve cell and the process of transporting signals from one cell to another can be written as software. It is clear that a natural nerve cell is more complex and that it is bound to more cells than an artificial one can be. The number of communication ports (synapses) of a natural nerve can vary from between 1,000 to 10,000.

An artificial cell produces output if the input value is over the cell’s threshold value; if this is not the case then there is no production. If there is output – as in natural cells – then this output is transported to the next cell group. Each cell produces its output as an input for the next cell.

A cell is separated into three groups: input, the hidden layer and output. Each group is considered to be made up of one layer, while the hidden layer can consist of more than one, according to the complexity of the job. As can be seen, the placement of the layers is similar in the process of the human body. We can compare the cells on the input layer with human senses. In this way we can teach a robot to avoid heat and cold, we can make them see and act according to this information. (Do not forget that a robot is in fact a computer.) It is natural that some sensors must be bound to the cells on the input layer. For instance, a sensor which is sensitive to heat can make the robot react to heat when the temperature is over the limit value or when the temperature is dramatically low it can move closer to a heat source. Or if pictures received from a video-camera are similar to an object that has been fed into the robot such data input can cause the robot to move to that object.

Artificial nervous systems are not only used in robot applications. They are commonly used in making clinical diagnoses, determining market-customer profiles, recognizing voices or pictures, classifications such as determining micro-structures, like germs and cell materials, economic profiles, energy sources, the futures of market shares, some predictive sciences, such as weather forecast, zipping data for computers, process control in industry, checking resources and some other matters in technological areas. As can be seen, there are many application areas for artificial nervous systems, all of which differ from one another.

The Basic Features of Artificial Nervous Systems

The features of artificial nervous systems can be simplified as follows: firstly, they can learn how to solve problems. In order to do this they use sample data and learning styles and while doing this they do not require any special help. Secondly, they can recognize important features and relations to help them distinguish different data forms.

When an artificial nervous system is operated, the first thing to be carried out is the training process. In order to do this, the program needs to have two alternating operations. It may obtain information concerning some results to be achieved, using results that come from the user, or the program is itself asked to produce some results. These two types of learning are not very different from how a human learns. One shows a young child an animal, and repeats the name. Now the child has learned the name of the animal and correlates it with the picture of the same. If no one teaches a child what a bird is, the child will all the same classify all animals that have wings and beaks and that have a certain physical shape, maybe even creating a name for the animal by him/herself. The difference between the computer and the human in this process is that a human has the ability to judge, while computers classify the animals according to their shapes and groups them thus. Naming and giving a naming feature to the computer is again a decision that a human will make. When the training process is finished, the data can be entered into the computer and the desired results can be attained.

Artificial nervous systems are changing and developing day by day. With each new development they become closer to the human nervous system; they are able to recognize different characteristics of different people and they are learning to make sorting decisions, even limited judgments. Whether or not these machines may one day enact a nightmare scenario, taking over from us is not a great threat, as whatever they are capable of doing is up to us to decide, as their “masters”. We should not fear these systems, but try to develop more of them; such systems help us in every day tasks, from drawing money out of the bank to our annual check-up at the doctor’s.

What is reality? What is illusion? Do we have free will, or is our life somehow preprogrammed? Such questions have vexed humanity from the beginning. Technology has added another wrinkle: virtual reality. Now that we can create reality, how do we know that what we consider reality is really real? Might we be in somebody elses virtual reality program?

External Reality

Nobody remembers being born. By learning about ourselves, we learn things from our surroundings and people, and how to experience events on our own. If our senses function normally, we begin to wonder about our sense-related experiences and seek meaningfulness: Who am I? How were I and the world created? Why am I here?

Each normal person is aware of himself or herself and the external world. We learn how to distinguish colors and shapes through sight and touch. But how would blindness or an impaired sense of touch alter our perception and understanding? Perhaps we would ask: Is the red that I see, the roundness that I see and touch, inside or outside of me?

No one can explain what red is. Yet we know what it is because people tell us that a ripe tomato is red, or that beaming the 620 to 740 nanometers wavelength into our eyes lets us experience redness. In both cases, someone else causes us to see red. Redness is also in the mind, for we can see it behind closed eyes. This is true for the other senses as well.

Recent brain studies reveal that neither light nor sound reaches our brain. Rather, it receives electrical stimuli produced by our senses and then processes them into meaningful sense impressions.(1) As the brain cannot distinguish between a real and an artificial electrical stimulus, we can make it see and respond to imaginary pictures as if they were real. When we see a red apple, what do we really see? What does its reality mean? Is it outside of us, are our senses tricking us, or is the world presented to us in another way?

What Is Virtual Reality?

Scientists and philosophers traditionally considered space and time absolute, as defined by Aristotle and formulized by Newton.(2) In other words, the space we inhabit existed before us and will exist after us, and time flows over and through it at a uniform rate. Modern science, particularly Einsteins theory of relativity, undermines this assumption.(3) Time and space are not absolute; they exist with us, partly because we invest them with reality and meaning. If we define real by what we feel, smell, taste, hear, and see, then real is simply electrical signals interpreted by our brain. The world may exist as part of a neural-interactive simulation, meaning that we might be living in a dream world.

Virtual reality is defined as a cartoon that we can enter; an interactive computer system so fast and intuitive that the computer disappears from our mind and leaves its generated environment as reality; and a computer-synthesized, 3-D environment in which more than one person can engage and manipulate simulated physical elements and interact with human representations or invented creatures.(4) Essentially, it is a hardware system that uses headgear, gloves, and other items to make us feel that we are in a computer program. Its core is a simulation system based on a programmed process that handles all interactions, scripted object actions, simulations of physical laws (real or imaginary), and determines the worlds status. This simulation is a discrete process that is iterated once for each time step or frame. Several systems can be coordinated to create a smooth virtual world.

Is Virtual Reality Possible?

As we are conscious beings, our senses gather data and transmit it to our brain for processing. But we cannot consider this data processing, which is a computers main task. We experience things; computers process data.

Virtual reality appears to go a step further because it creates a reality. Miniature screens in goggles, stereophonic sound in headphones, and a pressure-sensitive glove can create an illusory immersion in another 3-D space. But such informatic technologies still depend upon our sense organs to have any effect. Virtual-reality goggles display moving imagery to the retina, but that information must be transported along the optic nerve to the brains visual cortex. Only the brain can render this bio-information into conscious experience.

Theoretically, a computer can create a desired reality via an electrical stimulation of nerve fibers. The brain can be manipulated to see red by stimulating nerves in our retina, feel tension in our shoulders, and so on. Some say scientists can construct a virtual world that is just as real as the real world. Others disagree, citing two objections: the direct mind“body connection, and the necessity of simulating the entire universe.

The Direct Mind Body Connection: Pressing a finger causes a sensation in that fingera specific, visible location in 3-D spacenot in the brain or mind. But if we swing a numb leg, we feel a tingling sensation along it. This numbness and tingling is caused by a compressed nerve further up the leg, maybe in the knee, while the sensations paradoxically seem to be spread toward the foot. Apparently, the brain receives signals from a particular nerve fiber and imaginatively projects the resulting sensation back to the nerve ending. Since the brain receives only a bundle of nerve fibers bearing pulsed signals from the leg, and no information about where these signals originated, it assumes that they originated in the leg’s nerve endings and projects the sensation to that site. As the mind can be fooled, we can say that it creates a complete, subjective body image and then assigns all bodily sensations to specific locations. Do we press our physical or body-image finger? We press our body-image finger, for this is the finger recognized by the brain. Some people say that such feelings as love and toge-therness cannot be simulated. But they can, for the world we experience exists inside the mind and is projected onto the physical world. Seeing love in a spouse’s eyes is the result of light reflected from his or her eyes, focused onto our eyes’ retinas, and coded electrical signals transmitted from the eyeballs to the brain. Thus the only connection is one mediated by electrical (albeit biological) signals. Whether we have bionic or normal eyes is irrelevant, for what matters is the person behind the eyes, not the eyes’ mere visual apprehension. If a couple is immersed in virtual reality, they can still look into each others’ eyes in exactly the same manner. The same is true for togetherness and other feelings, as well as what our five senses experience. Simulating the Universe: This argument overlooks two points: First, we focus on certain things, relegating everything else to the background. Our optic nerve can be stimulated to ignore what we consider un-important. Second, as our sight and hearing are limited to a narrow spectrum of light and sound, the computer only has to focus on that particular spectrum.

An Interesting Experiment

A Ph.D. project in Manchester involves communicating with a robot located 40 miles from the lab.(6) Sensors in its hand read temperature, pressure, and humidity. When wired to a fast communication net, it sends collected data to a glove worn by an operator in the lab so that he or she can feel what the robot feels. This two-way communication system enables the operator to command the robot to move its hand and touch nearby objects by moving the glove. In one test, the hand touched a hot object and the operator’s hand felt the burn. The operator sees what the robot sees, thanks to two video cameras in the latter’s eyes.

What Would Happen If ? (7)

We can simulate a world. A normal brain stores at least 1018 bits and processes information at about 1015 bits per second.(8) Thus we can make an hour seem like a year. The subject will see changing seasons, solar and lunar movements, and lengthening and shrinking shadows. We know that our program causes these effects, but he believes cause and effect to be operative: Have you not seen how your Lord spread the shadowif He willed He could have made it still thus We have made the sun its guide (25:45). This verse indicates that the sun rises toward noon, and that shadows shrink and then begin to lengthen as the sun declines. The subject is limited by the program. For example, he appears to throw a stone, but only if the computer generates the necessary images and sensations. His action is virtual, as in: You killed them not, but God killed them. You threw them not when you threw, but God threw, that He might test the believers by a fair trial from Him (8:17). Let’s send in a virtual messenger to inform the subject of the programmer’s rules. If he does not obey, he will be punished. For example, we could easily rewrite the program to exclude sunlight. After terminating the program, the programmer could explain and demonstrate the truth of the virtual messenger’s words. The subject would have to accept the programmer’s control of, and his lack of influence upon, his life. This is a lesson for those who struggle with their perception of the physical world and the reality of the unseen spiritual world. Two Qur’anic verses show that such speculations are not so different from the subject’s virtual world: Say: Tell me, if God made night perpetual for you until the Day of Resurrection, who is a god beside God who could bring you light? Will you not then pay heed? (28:71), and: How can you reject faith in God? Seeing that you were without life and He gave you life; then He will cause you to die and will bring you again to life; and to Him you will return? (2:28)

Conclusion

For believers, such advances bring one question to mind: Are we living in a virtual world created by God? Most religions answer yes. Although their goals or understandings may differ, the main point is the same: Our life in this world is only a prelude of what is to come.

Footnotes

1. The Brain Tumor Foundation of Canada. Online at: www.oncolink.upenn.edu.
2. Online at: http://eserver.org/ philosophy and www-groups.dcs.st-and.ac.uk/history, respectively.
3. The Virtual Reality Store. Online at: www.thevrstore.com.
4. http://ksi.cpsc.ucalgary.ca.
5. Christianity, Judaism, and Islam consider this world a testing ground for the eternal life. Buddhism and Hinduism consider it an illusion that must be penetrated to achieve enlightenment.
6. Osman Kocak, Virtual Reality in Medicine (Ph.D. diss., Salford University [Manchester, UK], 1996).
7. Adapted from H. Baki, Virtual Reality (Ph.D. diss., Newcastle University [Newcastle, UK], 1997).
8. Ibid.

He was born in Cordova in 52OAH (1126) and named after his grandfather Abu al-Walid Muhammad ibn Ahmad ibn Rushd, who died in the same year. His grandfather was the Chief Judge in Cordova and the foremost authority in Maliki jurisprudence. To distinguish him from his illustrious ancestor, Ibn Rushd was later known as Ibn Rushd al-Hafid (the grandson).

Cordova, where Ibn Rushd grew up, was a thriving centre of all the diverse arts of civilization and culture attracting many great scholars from around the then known world to its wonderful libraries. Ibn Rushd studied and memorized the Qur’an and the Muwatta of Imam Malik. He was an excellent student of jurisprudence and quickly qualified to give legal opinions and sit as judge.

Following his work in the sciences of law, language and Hadith, he went on to study mathematics, astronomy and astrology and then medicine. He was a friend to the most prominent thinkers and writers of his age: Ibn al-Tufayl (d. 1186/6), author of the famous allegory Hayy ibn Yaqzan (said to have influenced Robinson Crusoe ); the philosopher, Ibn Bajja (Avempace in the West, d. 1139); the great jurist and judge Abu Bakr ibn al ‘Arabi (d. l148); the famous physician Abu Marwan ‘Abd al-Malik ibn Zuhr (Avenzoar in the West, d. 1161) and his son Abu Bakr (d. 1198).

Ibn Rushd served as a judge in Ishbiliya (Seville) in 1171 and then in Cordova two years later. His reputation for wide knowledge, correctness and fairness in giving verdicts, led to his appointment as Chief Judge. His book Bidayat al-mujtahid wa nihayat al-muqtasid (The reference for the searcher and the resort for the fair) remains an important reference for students of jurisprudence and is still taught in universities to this day. Although he was a Maliki he used the ideas of other schools of thought. Because he had so many activities and interests besides his public duties, Ibn Rushd had to organize his time very fully: he spent his days working as a judge, teaching, and in academic discussion with other scholars; he reserved his nights for reading and writing.

His friend Ibn al-Tufayl wrote to invite him to visit Marrakech, the capital of the Muwahhidun (Almohades) who had established a powerful and stable state in North Africa after they took over from the Murabitun (Almoravides), and were famous for their patronage of scientists, physicians, theologians and philosophers. Ibn Rushd’s intelligence, learning and ideas so impressed the ruler, Abu Yusuf ‘Abd al-Mu’min, that he was appointed to reform the educational system. This he did successfully before returning to Cordova.

When Abu Ya‘qub ibn ‘Abd al-Mu’min came to power, he appointed Ibn Rushd as his personal physician after Ibn Tufayl. Ibn Rushd held this post for a year (1183) when he was appointed as Chief judge. His success provoked court envy and he was falsely accused of heresy, in particular that he adhered too closely to the doctrines of Aristotle. He was indeed a supporter of Aristotle’s doctrines after these were properly reformed and adapted to Islam. Ibn Rushd fell out of favour at the court and was ill-treated. His books on philosophy were burnt, though his works on medicine and theology were not censored. When Abu Ya‘qub discovered he had been misinformed, he tried to invite Ibn Rushd back to apologise to him, but he was too late. Ibn Rushd died on 9th Safar 595AH (December 1198).

His writings

Ibn Rushd was broadly cultured indeed and wrote on many different subjects. Here we can mention only the most famous of his great works. In jurisprudence, as noted above, he wrote Bidayat al-mujtahid wa nihayat al-muqtasid (The reference for the searcher and the resort for the fair). In philosophy, he wrote Tahafut al-tahafut (refutation of the refutation), his response to Imam al-Ghazali’s famous Tahafut al-falsafa (refutation of philosophy). Ibn Rushd combined both philosophy and religion in mainly two books: Fasl al-maqal wa taqrib ma bayna l-shari‘a wa l-hikma min al-ittisal (an authoritative treatise on the convergence between the religious law and philosophy), and Kitab al-kashf ‘an manahij al-adilla fi ‘aqa’id al-milla wa ta‘rif ma waqa‘a fiha bi hasb al-ta‘wil min al-subah al-muzayyifa wa 1-bida‘ al-mudilla (an exposition of the methodology of demonstrating the creeds and description of the confusions and innovations in interpretation which confound truth and lead to error). In medicine, Ibn Rushd wrote the Kitab al-kulliyyat fi al-tibb (a general reference on medicine) which was translated into Latin and Hebrew and European vernaculars. It was a major reference in medicine though it never reached the standard of al-Qanun fi al-Tibb of Ibn Sina (Avicenna, d. 1037) which was used everywhere as simply T he Canon of Medicine.

Ibn Rushd had prepared this book especially for practising physicians and students of medicine. He apologised for the work’s brevity, a limitation he attributed to his preoccupation with commitments to judging, political affairs and philosophy. He advised those who sought greater detail to consult al-Taysir (The simplification) of Abu Marwan ‘Abd Al-Malik ibn Zuhr. Al-Kulliyyat is organized under seven broad headings or chapters:

1. Anatomy
2. The function of the organs
3. Diseases (pathology)
4. Syndromes: a brief clinical review
5. Health care, especially sports, massage and sleep
6. Medication and diet
7. Healing (particularly of different types of fevers).

The chapter on anatomy in al-Kulliyat

Ibn Rushd criticized the physicians and students of medicine of his time for neglecting anatomy. His own presentation of the subject is both concise and precise. He divides it into two major areas:

a. Anatomy of ‘simple’ organs such as bones, flesh, and veins.

b. Anatomy of ‘compound’ organs-for example, the arm which comprises bones, flesh, veins, tendons, nerves etc.

His description starts with the bones of the head and the teeth. 

Bones

There are six bones in the cranium and 14 in the upper jaw (the maxilla) and the ear, and two in the lower jaw (the mandible). All these bones are attached by seams except the two bones of the mandible that are articulately joined. This was later established as untrue-the mandible in fact has a single bone not two. The first to discover this was the physician and linguist ‘Abd al-Latif al-Baghdadi (Ibn al-Labbad). He examined 10,000 cadavers removed from the hills of al-Muqattam, east of Cairo, during the construction of a road. He realized this fact after observing thousands of examples. This was revealed in his wonderful book al-Ifada wa l-i’tibar fi l-umur al-mushahada wa l-ahwal al-mu‘ayana fi ardi Misr, (review and lessons from examinations and experiences in Egypt).

Ibn Rushd wrote of the teeth that there are 16 in each jaw-two central incisors, two lateral incisors and two canines, and five molars and premolars on both right and left sides. There are three or four roots in the maxilla but only two in the mandible, the remaining teeth have only one root.

He also described the large aperture in the back part of the skull, the foramen magnum, and its relation with the seven vertebra of the neck (cervical vertebrae), which have apertures on the sides. The vertebrae of the chest region are twelve; in the lumbar there are five, linked to the sacrum in which he counted three bones (in fact there are five) attached to the bone of the coccyx which is also composed of three attached vertebrae.

Ibn Rushd said that all vertebrae are articulate except the first two from the neck, because the first vertebra is attached to two appendices ramified from the skull.

He also said the bone of the sacrum is attached from the sides of the hips, in each of which is the acetabulum (socket) which contains the ‘head’ of the thigh bone (femur), often referred to as the ‘pomegranate’.

Ibn Rushd described in detail the bones of the front side starting from the clavicles up to the pubic bone, passing by the ribs and the bones of the shoulders. He also described the upper and lower limbs very precisely. What he wrote is not different from what we know today except that, for the bones of the arm, he uses ‘lower’ and ‘upper’ zanad (forearm) to mean the radius and the ulna. He indicated the bones of the leg, nowadays known as the fibula and tibia, in the same terms.

Veins and arteries

In the old days, the arteries were called the ‘beating veins’ (dhawarib ), and jugular veins were the ‘non-beating’ veins (ghayr al-dhawarib ). Ibn Rushd made a precise distinction between the two types of veins which remains accurate and valid. He wrote:‘Arteries come out of the heart whereas the jugular veins come back to it.’ He also described the difference precisely, the arteries are more solid and have two similar layers: the fibres of the inner layer are crosswise while the outer layer fibres are length-ways-even by modern standards a very professional anatomical description.

Two arteries of different size come out of the heart, the smaller one goes to the lungs and ramifies into them (pulmonary artery). The other (aorta) is larger, divided into many sections and ramifies into the whole body, one section going up to the head and upper limbs, another going alongside the vertebral column with branches leading to the chest and abdomen; it ends in the lower body and feeds the two lower limbs.

Ibn Rushd’s fascinating description is confirmed as correct and accurate. However, he failed to observe the circulation of the blood accurately. This was not properly described until nearly a hundred years later by Ibn al-Nafis (d. 1288) a Damascus-born physician who worked in hospitals in Cairo, and many centuries before William Harvey (1578-1657). 

The nervous system

The nervous system is the most complicated organ in the human body and its anatomy has only gradually become known over recent centuries. Nevertheless, Ibn Rushd was able to describe the brain, its membranes and the cranial nerves. He describes the smelling nerve perfectly, pointing out that it ends with a nipple like that of the breast. He does not consider this nerve as the primary one, giving that distinction to the optical nerve. The first pair of nerves issue from the brain and form the sclera inside the cranium, then come out to the eyes each from its side. This is a wonderfully precise description.

Ibn Rushd then describes the nerves that feed the muscles of the eye. According to modern anatomy, these nerves are the third, fourth and sixth, but Ibn Rushd considers them all as the second pair that ramifies in the muscles of the eyes. He considers the third pair as related to the next (the fourth), and these feed areas of the face, the ear, the palate and the nose-in fact, he was writing about the fifth and seventh pair of nerves according to modern anatomy. As for the fifth, Ibn Rushd says that a part of it leads to the ears and the muscles of the cheeks, whereas this is identified as part of the seventh pair.

Ibn Rushd writes that the sixth nerve feeds the pharynx and the tongue and part of it leads to the muscles near and around the shoulder and another part deviates to the neck and a branch of that goes to the larynx. This is actually the eleventh nerve (the accessory nerve) and there is some confusion in Ibn Rushd’s account with the description of the tenth nerve (vagus; the wandering or confused nerve). Although he attributes many characteristics of the vagus nerve to the accessory one, Ibn Rushd is very accurate in the description of the characteristics themselves. He observes that some of the branches of this nerve lead to the chest and feed the heart, lungs, and esophagus; that it runs through the diaphragm and makes the link with the cardiac and liver membranes, the spleen and the rest of the intestines/bowels.

Ibn Rushd describes the seventh nerve as starting from the back of the brain and ramified in the tongue: he is describing accurately the twelfth nerve (hypo-glossal).

He describes as accurately as modern anatomy does, the nerves that go along the vertebrae. He mentions the eight pairs of cervical nerves, sixteen pairs of dorsal nerves, and five pairs of lumbar nerves.

He misses the correct number of the sacral nerves, they seemed only three to him because they are very closely attached-in fact they are five. Three nerves come from the bone of the coccyx and a single nerve comes out on the sides from the middle. This is absolutely accurate.

Ibn Rushd wrote;

‘The brain has two nipple-shaped appendices that grow from its two advanced abdomens (olfactory bulb). They reach the bone that resembles the cribrium (cribriform plate), which is perforated with many holes [i.e. like a sieve], not smooth but rough with its position in the cranium, where it reaches the end of the nose.’

It would be very hard to improve on the concision or accuracy of this account even today.

About the membranes of the brain, he wrote, again with wonderful, inspiring accuracy:

The brain has two membranes, one is hard and thick (dura mater), and the other is thin (pia mater), they cover the brain very closely and in some locations are completely joined. The thick one is adherent to the cranium. This membrane has many perforations in two places, the first at the canal at the end of the nose (cribriform plate), and the second at the bone of the palate. Under the brain on the thick cover, there is the mysterious net composed of veins that go up to the head.’

The structure of eye

Ibn Rushd’s ability and competence as an anatomist is most clearly demonstrated in his description of the eye and its layers, which compares most favorably with what is known today except some minor differences in terminology. Ibn Rushd had even established the original development of the layers of the eye in the fetus, and discovered that they appear to imitate the layers of the brain and its membranes. Ibn Rushd combined accurate observation with brilliant exposition, sight with insight, presenting the structures of the eye as well as any twentieth-century expert could, and did so many centuries ahead of any physician in Europe.

He wrote:

The eye is composed of seven layers and three liquid areas. The first, from the side of the cranium, is a membranous layer that develops from the thick layer (sclera). The next layer from outside develops from the thinner membrane of the brain; it is called al-mashima (choroid). The next is a layer similar to the net (retina). It grows from the same nerve that comes out of the brain. In the middle of this layer, there is a soft and liquid area called al-rutuba al-zujajiyya (vitreous humour). Inside it, there is another spherical body but with some minor flatness. It is as clear as the ice and called al-rutuba al-jalidiyya , and we call it nowadays al- ‘adasa (lens).’

Ibn Rushd continues this wonderful description, by mentioning al-rutuba al-ma’iyya al-amamiyya (aqueous humour), he also called it al-rutuba al-baydhiyya because its liquid is similar to the soft liquid egg-white:

‘On the outside of this liquid appears a soft body whose inner texture is velvet-like, that follows the al-rutuba of baydhiyya (aqueous humour); smooth from the outside its colour is different from the body of the other, it can be very black or less dark or even blue.’ This is an extremely precise description of the iris (quzahiyyatu al-‘ayn) and the ciliary body (al-jism al-hudhabi).

He adds:

‘Inside the ciliary body, next to the lens, a hole that widens and narrows depending on the extent of darkness that it needs, the hole is called hadaqa (pupil) and the membrane itself is called the inabiyya (grape- like) layer.

‘Next to this layer, a cover that has a hard and clear white and thin plate which is called al-qarniyya (cornea). It takes the colour of the layer below it. On the top of this rises a white body called al-multahim (conjunctiva).’

Ibn Rushd also wrote about the physiology of sight:

‘The sight is not a thing that comes out of the eye as Galinius used to think. The eye receives the colours through the reflecting objects in which they are held, in the same way as a mirror does. Once the colours are reflected in the eye, the object is then conceived by the visioning power.

‘This could well be proved in natural science (physics). That is why any of those parts of the eye is able to reflect the colours because of its very glossy surface. So that body is the special tool to the lens and the advantage of the qarniyya (cornea) is . . . [that] it is made clear and thin so that it does not prevent the ice-like liquid (lens) from receiving the images.’

This is an accurate description of the eye and the physiology of sight that does not differ much from what we know today.

From this brief dip into a chapter of al-Kulliyyat fi al-Tibb , we realize the importance of the work of Ibn Rushd-jurist, philosopher, physician. He was an expert in each of these fields and the most distinguished scholar in Spain and North Africa. He neither experienced nor discovered any contradiction between his religion and his science; rather, his quest for knowledge and excellence, his wonderful curiosity, enlightened and improved his faith. His famous observation- who practises autopsy, his faith in God increases -should silence the false allegation that Muslims never practised anatomy and that they are against applied sciences. What has been written by so many Muslims in all fields of knowledge refutes this allegations. Medicine and the other applied sciences are a necessary and essential contribution to the well-being of humankind. Therefore, to work in them is fard kifaya , a collective obligation upon the community of Muslims as a whole, an obligation which some members of the community must undertake on behalf of the others who cannot.

Islam is the guide for those who seek true and sound knowledge in every subject. All sciences, so long as they are directed to God and not to merely worldly ends or personal glory, bring their students closer to God and make easier the way to approach and please Him: Those who fear God, amongst his servants, are those who have knowledge. And God is the Guide to the straight path.

The disease affects otherwise healthy individuals, usually young adults, with multiple lesions of the central nervous system. These lesions result in problems with co-ordination, slurred speech (dysarthria), numbness, paralysis, urinary incontinence and blindness. Sufferers often do not know which part of the body it will attack next.

Although humankind have made great advances in many areas, they have made little progress in understanding the brain and its operations. The starting point for understanding multiple sclerosis or any other neurological illness is an examination of the smallest unit of the brain, namely the nerve cell or neuron. The neuron is made up of a cell body (called a soma) and one or more long processes – a single axon and dendrites. The structure resembles tree trunks growing from a frizzle of roots (see diagram).

The roots, called dendrites, serve mainly to receive incoming messages from other neurons. The trunks, known as axons, transmit the messages and are covered with fatty insulating sheaths. These myelin sheaths are the focus of research into MS. The myelin contains a protein referred to as myelin base protein (MBP). Deterioration of this myelin sheath, particularly the MBP, is characteristic of multiple sclerosis. The myelin ensures that the electro-chemical charges communicated by the neurons are transmitted efficiently. If the sheath is damaged, signals ‘leak out’ causing the slurred speech, numbness, etc., associated with MS.

There are several approaches to dealing with MS. We can try to understand why the sheath becomes damaged in order to work out how to repair it. We can experiment with animals (typically rats), in whom MS-like symptoms have been induced, and search for a vaccine. Also, we can look to the body’s own healing system and try to understand why (for example) children do not normally get MS and whether the body can reverse the process ‘naturally’.

Whatever approach we take, we will never find a permanent cure unless we understand the complexities of the brain. So far, we have come nowhere near even a partial understanding of this marvel of creation. Fortunately, understanding all of creation is not a pre-requisite of searching for a cure.

One approach, as we noted, concentrates on finding ways of repairing the myelin sheath. This idea would have been unthinkable even a few years ago. However, in 1993, Charles French-Constant, at the Centre for Brain Research, identified re-myelination, that is, a reversal of the process, in newly formed lesions of sufferers experiencing the early stages of the disease. It appears that the body tries to regenerate itself but, with most MS sufferers, it is unable to do so fully. The basis of French-Constant’s research is that this regeneration might be enhanced if a chemical trigger could he found to improve the limited capacity for healing. His work starts by looking at the natural healing processes. Repairing even only 5% of the damaged nerve fibres would bring considerable relief to a large percentage of MS sufferers. For example, it could eliminate most bladder malfunctions related to MS. In effect, the disease would appear to he ‘contained’.

Humans are born with all the brain and nerve cells they are likely to need during their lifetimes. Throughout the life of living organisms, nerve cells die. If the cells which lead to the sheathing of the nerve cells could be found in an inactivated state in MS sufferers, and then encouraged to migrate, proliferate and repair the damage caused by the degeneration of the myelin, the processes of remyelination could be encouraged. The body would heal itself.

Research to identify the origin of the cells which end up insulating the axons began in the l98Os on rats. This work with rats suggests that these cells may still be present in fully developed adults, However, optimism must be cautious. As with other experiments, early results with cats have shown that scaling-up results is not always straightforward.

Even if the right cells can be found in the body, creating the correct chemical environment for regeneration is still going to be difficult. Another problem is that even if remyelination can be encouraged, this does not necessarily mean that de-myelination has been halted. The disease has to he attacked from both directions.

The new ‘vaccine’ about to be tried in America was developed by David Topham of St Jude’s Hospital in Memphis, Tennessee. Instead of trying to support the regeneration of the myelin, he attempts to stop the process that attacks the myelin sheath.

The body’s immune system, primarily in the form of T cells, naturally attacks antigens from viruses and bacteria which are seen as foreign organisms. In multiple sclerosis, the protein of the myelin sheath (MBP) is mistakenly attacked in the same way as an antigen might be.

In the early l980s, researchers found that they could reduce the number of cells which attack the myelin in a MS type illness in rats by inoculating them with inactivated T cells. In 1993, Jingwa Zhang managed to demonstrate a similar pattern in six humans using their own weakened auto- reactive T cells (Science, 261, p.145l). This was based on ‘naturally occurring cells’.

Bill Blackmore, at the Cambridge Centre for Brain Research, has been attempting to culture cells from donors. Others at the Centre have taken cells from patients in the early stages of re-myelination, cultured them in a laboratory and, after a severe attack, reintroduced them along with the necessary growth factor into the damaged area. This has the advantage that rejection is less likely.

A more controversial approach uses post-natal tissue. Cultured fetal tissue has been used in Sweden and America in an attempt to treat Parkinson’s disease. But this procedure raises a number of serious ethical questions.

Any significant breakthrough in the treatment of MS is likely to have implications for the treatment of arthritis. This is what is hoped for with the latest attempt to find a cure. Earlier this year, 300 Americans suffering from severe rheumatoid arthritis were treated with a drug which aimed to ‘re-educate’ the T cells. It was hoped that this would result in them protecting the relevant cells rather than destroying them. The manufacturers claimed that four people were completely cured of the illness. The results were encouraging. A peptide produced by Topham, the developer of the latest vaccine, has already been used on joint tissue by other research groups.

These attempts to ‘cure’ MS may produce results, but all the researchers will admit that the central problem is lack of knowledge about how the brain operates. Much of the nervous system is still a complete mystery. The search for a cure will continue to go on. There is a cure and we have to search for it, for we have been assured that ‘for every illness there is a cure’.