From faith traditions to modern neuroscience, the quest for knowledge is regarded as essential for both progress and well-being. With more than a third of the world’s population suffering from neurological disorders such as Alzheimer’s and Parkinson’s disease, learning how to maintain brain health has never been more vital (GBD, 2016). Recent research has shown that the brain, once believed to stop developing with age, actually possesses a remarkable capacity to adapt and reorganize itself—a phenomenon known as brain plasticity (Maguire et al., 2000). While age and stress can impede this process, continuous learning has emerged as one of the most effective methods for improving brain function and delaying cognitive decline (Park & Bischof, 2013). In this article, we will look at the relationship between learning and brain plasticity through the prism of one of the divine names of God: “The Restorer” (al-Mueed). By investigating how mental challenges and lifelong learning might help heal and strengthen the brain, we may be able to counteract the consequences of neurodegenerative disorders.

The link between aging and brain deterioration

As people grow older, their risk of developing neurodegenerative disorders like Alzheimer’s and Parkinson’s disease increases considerably (Alzheimer’s Association, 2020). These conditions, which affect millions worldwide, are often associated with progressive brain deterioration. Alzheimer’s is characterized by memory loss and cognitive deterioration, whereas Parkinson’s largely affects movement and coordination (Jankovic, 2008).

Scientific studies indicate that the brain changes significantly with age. The brain’s overall volume begins to shrink, especially in regions crucial for memory and learning (Raz et al., 2005). Neurons, the cells that transmit information in the brain, also shrink, as does the number of synapses, or connections between these neurons. These changes result in slower cognitive processing, memory loss, and decreased problem-solving ability.

The fundamental question, therefore, becomes: Can the brain’s ability to expand and make new connections be repaired or strengthened in the face of aging? New research on brain plasticity reveals that with the correct inputs, particularly through continuous learning, the brain can adapt and function well into old age. This offers promising new avenues for improving brain health and combating neurodegenerative diseases.

What is brain plasticity?

Brain plasticity, or neuroplasticity, refers to the brain’s remarkable ability to reorganize and rewire itself (Kolb & Gibb, 2014). It enables the brain to form new synaptic connections throughout life, adjusting to learning, experiences, and even injury. One of the primary advantages of brain plasticity is the potential to reverse the detrimental effects of neurodegeneration. As neurons deteriorate due to aging or disorders such as Alzheimer’s, the brain can partially compensate by strengthening existing connections or establishing new neural pathways. This technique can improve cognitive capacities such as memory, learning, and problem-solving. A powerful example of plasticity in action is the ability of an individual to regain movement after a stroke. By rerouting signals to undamaged areas of the brain, people can often regain lost functions and restore a sense of normalcy in their lives (Murphy & Corbett, 2009). This demonstrates the tremendous potential of the brain’s ability to rewire itself for treating neurodegenerative diseases.

Barriers to brain plasticity

While brain plasticity offers hope for cognitive recovery, several obstacles can impede this process. One major factor is stress, which has been shown to reduce neuroplasticity. Chronic stress triggers the release of cortisol, a hormone that damages neuronal connections and impairs the brain’s ability to establish new ones. This can hinder cognitive flexibility, making it more difficult to acquire and adapt to new information. Another barrier is age and inactivity. The brain’s plasticity decreases as we age, especially if we engage in less mental and physical exercise (Salthouse, 2009). Neurons shrink and synapses deteriorate, making it difficult for the brain to form new neural connections. This is why active learning and engagement are critical for preserving brain function as people age. Finally, as we age, the brain attempts to strike a balance between plasticity and stability. While some flexibility is required for adaptation, excess plasticity can lead to instability. Therefore, as we get older, the brain increasingly prioritizes stability, which can make it more difficult to recover lost functions.

Understanding neurodegeneration

Neurodegeneration refers to the progressive loss of neurons and the deterioration of brain functions, often seen in conditions like Alzheimer’s and Parkinson’s. This gradual decline in brain health leads to memory loss, cognitive impairment, and motor difficulties. This relates to brain plasticity, where evidence shows that maintaining mental activity plays a vital role in slowing down neurodegeneration (Kolb et al., 2010). Engaging in cognitively stimulating tasks can enhance plasticity, allowing the brain to form new pathways that compensate for lost functions. However, neurodegeneration presents significant challenges. Harmful cellular build-ups, such as amyloid plaques and tau tangles, disrupt communication between neurons and hinder the brain’s ability to function properly. These biological barriers make it more difficult to fully restore lost cognitive abilities.

How to enhance brain plasticity

Learning and plasticity share a directly proportional relationship, where engaging in repetitive, challenging learning activities strengthens brain plasticity by encouraging the formation of new synaptic connections. Studies show that complex learning tasks—like learning a new language, solving puzzles, or playing an instrument—can promote neuron survival and stimulate brain reorganization (Park & Bischof, 2013). This process is especially important for preventing cognitive decline in older individuals.

Studies have linked difficult mental tasks to improved brain function, as they force the brain to adapt and evolve. Researchers have found that seniors who regularly engage in learning activities show a reduced risk of developing neurodegenerative diseases. In practical terms, consistent mental stimulation through ongoing learning can be a powerful tool for preserving cognitive abilities as we age. Regularly practicing new skills, engaging in hobbies, and challenging oneself mentally can enhance brain plasticity, contributing to overall brain health.

Many faith traditions prescribe lifelong learning, which aligns with the concept of brain plasticity. Prophet Muhammad, peace be upon him, encouraged seeking knowledge from the cradle to the grave, reflecting the idea that our minds have the potential to learn, grow, and adapt throughout life. This constant pursuit of knowledge is not only a spiritual endeavor but also a scientifically supported method to maintain brain plasticity and cognitive function as we age. Viewed through the lens of neuroscience, seeking knowledge can be seen as a form of exercising the brain. Reading the scripture regularly, memorizing prayers, and engaging in contemplation continuously strengthen neural connections and enhance cognitive abilities. Research shows that lifelong cognitive activities, such as reading and memorization, build cognitive reserve and slow the progression of neurodegenerative diseases by reinforcing neural connections and preserving brain function (Wilson et al., 2013).

One of the beautiful names of God is “The Restorer,” (al-Mueed). This name signifies God’s ability to bring life back to what was lost or broken, offering both physical and spiritual renewal. In the same way, brain plasticity mirrors this divine attribute, as the brain has an extraordinary capacity to reorganize and restore itself after injury or through consistent learning and mental activity. The concept of Al-Mueed not only speaks to physical restoration but also to the idea of spiritual renewal—just as faith offers believers the opportunity to return to a path of righteousness, repentance, and personal growth, brain plasticity offers the chance for cognitive recovery and adaptation. For instance, in cases of brain injury or degenerative conditions, neuroplasticity allows for the healing and rebuilding of cognitive functions, providing a second chance for the individual to regain what was lost. This parallel underscores a meaningful relationship between faith and science. Where Al-Mueed revives the soul, brain plasticity revives the mind, and both processes require continuous effort and faith. The path of seeking knowledge and engaging in prayer can be seen as acts of spiritual and cognitive restoration. These practices not only reinforce spiritual beliefs but also stimulate the brain, building new neural pathways and preserving mental acuity, especially as one ages. Just as the faithful believes that the soul can be rejuvenated through faith, repentance, and turning back to God, the brain too can experience renewal through learning and engagement.

In conclusion, understanding brain plasticity in conjunction with the teaching of faith traditions offers a valuable perspective on the significance of lifelong learning. By embracing the concept of “The Restorer” and consistently engaging in mental activities, we can foster cognitive resilience and promote better brain health, ultimately reducing the risk of neurodegenerative diseases. This not only strengthens the individual’s cognitive capabilities but also reflects the belief that our pursuit of knowledge is a path to both intellectual and spiritual fulfilment.

References

• Alzheimer’s Association. (2020). 2020 Alzheimer’s disease facts and figures. Alzheimer’s & Dementia, 16(3), 391-460.
• GBD 2016 Neurology Collaborators. (2016). Global, regional, and national burden of neurological disorders 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016. The Lancet Neurology, 17(11), 1224-1232.
• Jankovic, J. (2008). Parkinson’s disease: clinical features and diagnosis. Journal of Neurology, 255(S5), 3-8.
• Kolb, B., & Gibb, R. (2014). Brain plasticity and behaviour. Nature Reviews Neuroscience, 15(12), 121-131.
• Maguire, E. A., et al. (2000). Navigation-related structural change in the hippocampi of taxi drivers. Proceedings of the National Academy of Sciences, 97(8), 4398-4403.
• Murphy, T. H., & Corbett, D. (2009). Plasticity during and after stroke: rehabilitation and the role of the growth factors. Neurobiology of Disease, 37(1), 157-167.
• Park, D. C., & Bischof, G. (2013). The aging mind: neuroplasticity in response to cognitive training. The Psychology of Learning and Motivation, 59, 23-59.
• Raz, N., et al. (2005). Age and sex differences in the development of the frontal lobes: a longitudinal MRI study. Neuropsychology, Development, and Cognition. Section B, Aging, Neuropsychology, and Cognition, 12(1), 50-68.
• Salthouse, T. A. (2009). When does age-related cognitive decline begin? Neurobiology of Aging, 30(4), 507-514.
• Wilson, R. S., et al. (2013). Cognitive activity and cognitive decline in older persons. Neurology, 81(4), 337-343.

Our brains consist of many different types of cells, including astrocytes, microglia, and neurons. These are the cells that people are indirectly referring to when you hear someone say that hitting your head can cause permanent damage even though the initial impact was a minor one. They are the primary cells that are responsible for signaling functions, and one can see this in their shape because they resemble an electric cord. The dendrites receive signals, process them in cell bodies, and send an output signal via the axons and synaptic terminals (Figure 1). These cells cannot multiply, and our heads never get larger, so it begs the following question: how do we continue to learn and store information? The answer is long-term potentiation (LTP).

LTP is when synaptic connections between neurons become stronger with frequent activation. Neuronal activation is an electrical signal called an action potential that emerges due to a change in ion locations resulting in electrical potential that generates a nerve impulse (Figure 2). When the same neurons keep getting activated, again and again, a shortcut is created. We have two crucial receptors that play a role in this mechanism: AMPA and NMDA. AMPA is activated first because a Mg2+ ion blocks NMDA. As AMPA gets activated, the neuron becomes depolarized (due to the previously mentioned electrical changes). Now, the neuron is more positive overall, which will push the Mg2+ ion out of the channel, which is called the Law of Attraction in physics (i.e., opposites attract). With the Mg2+ ion removed, calcium ions can move freely through the NMDA receptor, and this influx of calcium initiates cellular mechanisms that cause more AMPA channels to be produced and placed on the synapse of the neuron, making the pathway activated quicker and quicker (Figure 3). These pathways become a default, and this is called long-term potentiation. The opposite of long-term potentiation is long-term depression, a decrease in synaptic strength, so if “you don’t use it, you lose it.”

Long-term potentiation is thought to be a way in which the brain changes in response to experience, and thus may be an underlying mechanism for learning, retaining memory, and even overall physical health. With long-term potentiation our default pathways are formed; so if we train ourselves to be anxious and stressed individuals, then we will be at an increased risk for developing hypertension, heart disease, cancer, and almost any other physical illness. We often forget that stress itself is a risk factor along with other lifestyle choices such as diet and regular physical activity. An interesting article, “The Science of Happiness: Why Complaining is Literally Killing You,” delves into this point of view:

“When your brain is firing off these synapses of anger, you’re weakening your immune system; you’re raising your blood pressure, increasing your risk of heart disease, obesity and diabetes, and a plethora of other negative ailments… This is why it is so important to spend time with people who lift you up. Want to be happy? Surround yourself with happy people who rewire your brain towards love.” (http://www.curiousapes.com/the-science-of-happiness-why-complaining-is-literally-killing-you/)

Long-term potentiation is also the basis of cognitive-behavioral therapy, which is a form of psychotherapy treatment that is goal-oriented and takes a practical approach to problem-solving. Cognitive-behavioral therapy recognizes the underlying mechanism of long-term potentiation: neurons that fire together wire together and puts it to good use by trying to change default patterns of thinking and behavior. By changing these default patterns, the result changes how we feel. For example, a common practice in cognitive-behavioral therapy is to keep a daily gratitude journal. The therapist may ask their client to write three things they are grateful for each morning and each night, whether it be something as simple as having water to drink or a significant life event. Forcing yourself to make these connections continuously, and being in a default repetitive state of gratitude, has been scientifically proven to decrease rates of depression and other mental illnesses.

Another perspective we can approach LTP from is from the lens of faith and prayer since prayer has an element of repetition in it. In his book, Fethullah Gülen: A Life of Hizmet, Jon Pahl states that “Peacebuilders pray, and prayer is a nonviolent practice. Even more: prayer has power. The power of prayer is neither political nor miraculous. Personally, prayer builds confidence. The repetition of prayer comforts a troubled mind with the solace of the familiar. Culturally, prayer builds trust. Communing with God and others can make any challenge seem surmountable. Socially, prayer builds movements.”

Yes, if we could rewire our brains towards love and peace with each prayer, we could find comfort and peace, and build bridges with those around us. In 2019 alone, the Islamic scholar Fethullah Gülen Hodjaefendi, mentioned the word “neurons” in his weekly sermons nine times, a fascinating statistic for a scholar who is neither a neuroscientist nor psychiatrist. Some excerpts from these sermons include:

“[when recited and listened to a couple times during the day and in the Tarawih Prayer] the Qur’an will establish itself better in our minds; our neurons will open their doors like the doors of a castle to the Qur’an and say ‘enter.’ Therefore, who knows how many times a day, a reunion will be established with the Qur’an.” (Ramadan: The Month of Mercy, Hope and Abundance on May 10, 2019)

“Bediuzzaman says: ‘Even if we had four hands instead of two, they would not be sufficient to do things we need to do.’ … In this case, we must send orders to the millions of neurons in our brain at the same to dedicate them all to the same task. … God opens you a window to exit. (Means for Serenity and Talk of the Beloved on April 4, 2019)

“[‘The entire universe is a great book of God; the meaning of each letter is nothing but God.’] Just as you … use all of your neurons to see the endless possibility of bounties, lined along like a gallery as if He is to say, ‘see and think as you walk this gallery.’ (Sorrow, the Spiritual Heart and Tongue on March 29, 2019)

To return to the biological aspect of neurons, one key component that is also valuable to synthesize all the information we have just covered, and that is the concept of “mirror neurons.” When we observe another person these mirror neurons start to fire and a kind of virtual reality simulation is formed in our minds, contributing to the construction of a theory of our intentions. For example, when someone smiles, you want to smile back; when someone gets a paper cut, you feel their pain; or when someone cries, you cannot help but cry as well. These are all phenomena explained by mirror neurons. Mirror neurons explain empathy on a biological level and are present even in animals.

From a multi-disciplined approach, including biological, psychosocial, and spiritual perspectives, one lesson becomes clear: we have the free will and responsibility to carve our default pathways. To make sure these default pathways are filled with love, peace, serenity, alongside discipline, patience, and resilience is paramount to our personal and collective health. By defining our own neural pathways, we will also be building our community’s networks since neurons mirror each other.

This study is a part of the burgeoning field of neuro-cardiology. It began when Armour and Ardell discovered a web of neurons in the heart. This web is described as being like a small scale brain, and it is endowed with functions like learning, data processing, remembering, and cognition – and it performs these independent of the central nervous system. These neuron cells in the heart both maintain communication with the brain and regulate the heart’s functions. Thus, a two-sided information transfer between the heart and brain is realized. In 2010, research conducted in different centers demonstrated that more information is sent from the heart to the brain, than vice versa.

Specific findings (McCraty, 2002, 2010; Haspel, 2009) have drawn particular attention to the relationship between the heart and brain, and they reveal that the heart communicates with the brain in four different ways:

1. Neurons (the neurological way)
2. Hormones and neurotransmitters (the biochemical way)
3. The pulse waves produced by blood pressure (the biophysical way).
4. The mutual transaction of electromagnetic fields.

The heart’s two-sided communication network with the brain and other bodily systems is one of the most complex communication systems known to humankind. While the brain has abstract, analytical, and logical intellects as well as functions like thought processing, data storing, and remembering, the heart is endowed with the intellects of feeling and communication. It is the center where feelings are first produced, and these emotions are then conveyed by the limbic system. In addition, the brain’s response to these emotions not only impacts all cells, but also the heart and brain waves of other people in the same vicinity.

Each heartbeat pumps blood, but it also sends and receives data to and from the entire body via neurological, hormonal, and electromagnetic means.

The same research from 2010 showed though the heart is the root of these functions, it also has functions relating to judgment, decision making, data-processing and remembering, just like the brain. The science of neuro-cardiology seems likely to radically change how we perceive the human body and soul.

The beating heart’s influence on our lives

The time that passes between heart beats is described as “heart rate variability.” Heart rate variability (HRV) reflects whether electric signals by the sinoatrial node (a group of nerve cells responsible for the electric current in the heart) is healthy or not. As HRV measures the heart’s ability to respond to the signals coming from and going to the brain, understanding the variability ratios of the heart has gained importance in recent years.

HRV is not always constant. The research conducted by Thurber et al (2010) studied HRV’s influence on a person’s mood, and it yielded interesting findings. According to their study, if HRV is consistent, all the body’s systems are positively influenced, or negatively if the HRV is inconsistent.

Depending on the emotional state of the individual, the heart influences the brain stem, amygdala, and cortex via the data it sends by means of heart rate variability. All of these findings indicate that the heart is not only given the duty of pumping blood, but also of being an administrative signal center that regulates the entire operation of the body in rhythm. When individuals experience different emotions like rage, joy, fear, or despair, the rhythmic patterns in HRV also differ.

For example, if a person is experiencing positive feelings like gratitude, appreciation, love, or mercy, the heart rate variability is consistent; but if the person is experiencing negative feeling such as fear, anxiety, despair, depression, or the like, the HRV becomes inconsistent. In addition, if the person is experiencing positive feelings, the heart perceives other positive feelings with more ease; and if not, the perception of such feelings becomes more difficult. Thankfully, the research conducted by McCraty et al (2009) and Halpel indicated that it is possible to intentionally evoke positive feelings in a person. External factors play a major role in our moods.

The electromagnetic field of the heart and its influence on our lives

The human heart is a reactor where the strongest and widest electromagnetic field in the body is produced. The bio-electromagnetic field produced in the heart has been measured to be 50-70 cm wide by magnetometers with a base of superconducting quantum interference device (SQUID). According to McCraty’s measurements of the heart’s electric field, which can be measured with an electrocardiogram (EKG), it is, on average, 100 times greater than the electroencephalogram (EEG) recorded in the brain – and the magnetic component is an average of 5,000 times stronger than the one produced in the brain.

The changes in blood pressure, sound pressure, and electromagnetic waves – all of which are produced by the rhythmic activity of the heart – are perceived by every organ and cell in the body. For instance, electromagnetic waves sent from the heart affect brain waves. Recent research by Haspel as well as Bedell and Kaszkin-Bettag suggest that the heart is where emotional states originate – the brain is simply sensing these feelings.

For instance, when the heart rate variability is 0.10 hertz, there is complete harmony between our body and spirit. In this state of harmony, it was observed that the waves from the two lobes of the brain are in the same phase and they turn into a single wave. In other words, the two lobes of the brain begin to work in perfect harmony. In addition, it was observed that at this state the brain secretes a serious amount of endorphins, which are the source of the feeling of pleasure.

Science is beginning to show that if the waves formed by HRV and brain waves are harmonious, a person will be physically and psychologically healthy. If the two sets of waves are not harmonious, the person is likely to be ill. This indicates that the changes observed in pulse patterns over time are a key measure of the balance between the brain and heart.

At the same time, this balance varies according to our mood. Attaining harmony only happens only when we experience feelings such as compassion, love, affection, appreciation, forgiveness, and thankfulness (Thurber et al, 2010; McCraty and Reese, 2009). A great deal of this harmony is realized through electromagnetic communication, which also strengthens our senses, concentration, and ability to generate new ideas. And physically, our immune system is strengthened, stress is reduced, and we are overall healthier. The equation is simple: good moods equal good health.

In addition to all of these benefits, a 2002 study by McCraty showed that a magnetic area of influence that surrounds the body is formed with every beat of the heart (figure 2). While the heart influences the functioning of our bodily systems with the data it sends to all cells and to the brain, it also influences other people’s hearts and brainwaves by sending out external data. In many instances, we witness that being close to certain people may both influence our heart (feelings) and brain (thoughts and decision making processes). This explains how parents and educators who constantly share the same environment with children can have a great impact in their lives. For this reason, all people, but particularly parents and teachers, must be very careful about what passes from their heart. It is ultimately our body’s functions turned into external action that have the greatest influence on those around us.

The following statements from the Prophet Muhammad, peace be upon him, summarizes this issue well:

• “God does not look at your bodies nor your forms, but He looks at your hearts and your actions.”[1]
• “There is lump of flesh in the body, the nature of which is that when it is sound, the entire body is sound, and when it is corrupt, the entire body is corrupt—it is the heart.”[2]

[1] Sahih al-Muslim, Birr, 33.

Let us start with the building blocks of the system, which are the nerve cells (also called neurons). The main function of nerve cells is the transportation of signals through electrical pathways. The morphology of neurons is entirely different from that of other types of cells, and this is what helps the nervous system function effectively.

The typical nerve cell can be broken down into three parts: the dendrites, the body, and the axon. The signal enters the nerve from the dendrites, runs through the body, and leaves the cell by way of the axon. The head of the nervous system is the brain. As only one part of the system, the brain is formed of about 80 billion neurons. Apart from the brain, there are billions more neurons in the nervous system, which runs throughout the body. Other than the neurons, there are neuroglia in the brain, which consist of approximately another 80 billion cells. In the brain alone, there are over 160 billion cells whose only purpose is to transport signals. But where do these signals originate from and where are they taken to?

The functions of the nervous system are performed through three main categories. The first category is the central nervous system (CNS), which is made up of the brain, the brainstem, and the spinal cord. This part is the center for decision making. The second category includes all the cells in the body apart from the nervous system, such as sensory cells and muscle cells. The final category is the peripheral nervous system (PNS), which seeps through the body and is the messenger between the CNS and the rest of the body. The whole function of the nervous system boils down to the transfer of electrical messages between these two ends.

An example is when a finger touches a flame. The sensory cells on the tip of the finger produce a “Hot” signal, and pass this electric signal on to the PNS. The PNS then transports this signal to the CNS, where electricity is translated into a meaningful message. The CNS then produces a “Withdraw” signal and sends it via the PNS to the muscles of the finger, which in turn withdraw the finger from the flame. This reflex does not even reach the brain and is processed in the spinal cord due to its simplicity. It is as if the brain cannot be troubled with such petty tasks. Slightly more complex tasks go up a little bit further to the brainstem. The tasks brought to the brainstem are not sudden reflexes, but do not require thinking, either. Some examples are chewing, swallowing, maintaining balance, and eye movement. The brain, however, performs the most complex tasks, such as sight, language, learning, and emotion.

Now that the signals’ pathways are clear, we must ask how exactly do cell groups in the central nervous system know how to react to various situations? How can a small group of nerve cells in the cerebellum (attached to the brain) decide to make the body lean to the left while falling to the right? How does a tiny spec of neurons in the pons (located in the brainstem) know when to start secreting saliva in the mouth? How are miniscule unconscious cells entrusted with decisions concerning the well-being of the entire body? They cannot see the area they are controlling. The only thing that comes to these cells is electricity. How on Earth do these cells know so much from only electric signals?

Let’s look at balance, but keep in mind that every mechanism is totally unique and they cannot be categorized into three or four groups. Our journey begins in the depths of the ears. There are three canals called the semicircular canals, which are all perpendicular to each other. The tip of each canal is filled with a thick fluid called the endolymph. On the bases of these tips are hair-like receptors. The thick fluid flows within the canal in accord with gravity, thus tilting the hair-like receptors. If these receptors tilt to one side, they generate a large amount of electricity. If they tilt to the other side they generate a small amount. Each canal represents one axis, and signals from all three canals make up a 3D world. Signals from each canal continuously flow to the small group of neurons in the cerebellum and are combined to make up a map of how the head is positioned. For example:

• The signal from the X-axis canal is high intensity. (This may mean the head is tilted right.)
• The signal from the Y-axis canal is low intensity. (This may mean the head is tilted upward.)
• The signal from the Z-axis canal is high intensity. (This may mean the head is tilted to the front.)

These three signals combine to give the coordinates of the position of the head. In this example, the variation is in the intensity of electricity. But in other signaling pathways, the variation may be in other features of electric signals, such as the frequency, the pattern, or the combinations of all of these. So by “reading” these different inputs of electricity, blind and deaf cells can “comprehend” complex situations and act accordingly.

It really is unbelievable how such sophisticated information can be simplified. This system may ring a bell to some of you: the main operating principle of the computer is exactly the same. Mere numbers, 0 and 1 (the signals), can combine to form complex information that the processor (the brain) can use to complete tasks satisfactorily. Yes, the brain is effectively a supercomputer capable of processing millions of signals every second in order to keep the body in check. It is capable of increasing its processing speed and can be trained to learn new things. Its memory capacity cannot be filled throughout a lifetime of learning, and it has a supporting system (the neuroglia) which optimizes its performance. It does not require any updates and can work without rest for over 100 years. It is compact and extremely lightweight. Of course, such a wondrous supercomputer requires a lot of resources in order to keep functioning. Although the human brain represents only 2% of the body’s weight, it receives 15% of the blood pumped from the heart, consumes 20% of total body oxygen, and utilizes 25% of total body glucose.

What we have talked about so far concerns around 80 billion neurons. Well, what about the other 80 billion we mentioned earlier? They are called the neuroglia and their main purpose is to lighten the neurons’ load. These cells form the environment in which nerve cells can operate most efficiently. Sounds simple enough, right? Well, we need to consider the fact that neurons handle delicate cargo. The signal formed by one end of the communication channel has to reach the other end with no change or loss in its features (frequency, intensity, pattern, etc.). A single mishap may generate serious consequences. The environment that the neuroglia are entrusted with includes molecular content, temperature, electrical stability, blood flow, and much more. No wonder there are 80 billion of them assigned to this job!

Let’s take a look into the types of neuroglia and what they do. First of all, there are the microglia. These guys are the bodyguards of the brain. They are actually specialized macrophages, which are a part of the immune system. In the case of brain damage, they sweep the area clean of any bacteria that may have infected the site.

Another type of neuroglia is the astrocytes. These cells are in charge of the blood flow to the neurons. They connect the nerve cells to the blood vessels and control the flow of blood by either dilating or constricting the vessels. They also constitute the majority of the “blood-brain barrier”. The blood-brain barrier is the border between the regular blood of the body and the fluid the brain swims in. The astrocytes in this barrier are like the chefs of the brain, selecting what is in the neurons’ menu. They allow only specific molecules through the barrier, meeting the needs of the brain during high activity and preventing waste during low activity. A third type of neuroglia is the ependymal cells. These cells produce the fluid the brain swims in, called the cerebrospinal fluid. Together with the astrocytes, they help form the optimal vital fluid for the brain. One final type of neuroglia is the oligodendrocytes. Oligodendrocytes form the specialized “myelin sheath,” which can be compared to a blanket. This sheath wraps around the nerve cells in the CNS, isolating them electrically. This isolation is key in the preservation and fast transportation of electric signals.

To conclude, the nervous system is extremely complex. Within this complexity, we find beauty beyond speech. How are these seemingly distant cells and organs in touch with each other through just electricity? With what decision-making mechanism can mere unconscious cells make such critical moves? We only have surface level knowledge of these mechanisms. But one other crucial question is how these cells managed to form such a complex system in the first place. They couldn’t have gone through the process of trial-and-error because error means certain death for such an intricate mechanism. So, did the cells gather around and engineer this perfect system by brainstorming? Were they capable of combining limited organic resources to design a brain that all of mankind could not even come close to after thousands of years of advancement? Ask your brain!

Observing Majorana fermions in the ferromagnetic atomic chains on a superconductor. Nadj-Perge et al. Science, October 2014.

In the universe, matter and antimatter particles are always produced as a pair and, if they come in contact, they destroy each other in a flash of energy. In 1937, an Italian theoretical physicist named Ettore Majorana had proposed that there can be unique exceptions to this rule: a stable particle could exist in nature that is both matter and antimatter. Scientists have been looking for that indefinable particle, also known as the “Majorana fermion,” for seventy years. A group of researchers recently reported that they were able to detect the Majorana particle which behaves simultaneously like matter and antimatter. Researchers designed an experimental system allowing them to observe an emergent particle inside a material. They first generated an extended chain of pre magnetic iron atoms on a superconductor made of lead. Then, they cooled the material to -272 C, just about one point above absolute zero, and monitored it using a giant two-story-tall scanning-tunneling microscope, which can track electrical signal changes with very high precision. Finally, they were able to capture a glowing image of an electrically neutral particle at the ends of atomically thin iron wires. The Majorana particle was surprisingly stable and the opposing properties make the particle neutral so that it interacts very weakly with its environment. The discovery of the Majorana particle has exciting implications for several areas of modern physics, engineering, and astrophysics. For example, Majorana particles are very similar to neutrinos, as they both have very weak interactions with the matter. Neutrinos are thought to make up most of the dark matter that fill the Cosmos. Perhaps, neutrinos are simply Majorana-like particles and Majorana particles are also a candidate for what dark matter is. As an industrial application, Majorana particles can be utilized in quantum computing which aims to create computers to handle incalculable systems. The current quantum computing technology uses electrons, but they are known to be very unstable due to high interaction rates with surrounding materials. However, since Majorana particles are neutral and highly stable, they can be engineered into a variety of materials to produce more reliable and powerful quantum computing applications.

The Bitter Side of Artificial Sweeteners

Artificial sweeteners induce glucose intolerance by altering the gut’s microbiota. Suez J. et al. Nature, September 2014.

There have been conflicting and confusing findings about the health effects of artificial sweeteners over the past several decades. Some studies found that they cause weight loss and others found the exact opposite. Some studies linked them to diabetes and other studies argued otherwise. A recent study provided a series of experimental evidences that artificial sweeteners disrupt the body’s ability to regulate blood sugar, and thus may cause metabolic diseases and diabetes. Researchers, using animal models and human studies, found that sweeteners significantly alter the gut’s microbiome – the collective name of bacterial colonies living in our intestines. The composition of our gut microflora plays a critical role protecting us from pathogenic bacteria, the metabolism of indigestible components of our diet, and modulating development and regulation of the immune system. Sweeteners – in the form of saccharin, sucralose, or aspartame – are found to alter the mix of microbes in our intestines and consequently change how our bodies metabolize glucose. Constant use of sweeteners in mice and human test groups caused typical glucose intolerance symptoms in which glucose levels rose higher after eating and declined more slowly than expected. Glucose intolerance can ultimately lead to serious illnesses like metabolic syndrome and Type 2 diabetes. Although this study will cause a lot of discussions and headaches in the food industry, the link identified between microbiome and glucose intolerance will definitely inspire novel therapeutic approaches to metabolic disorders such as diabetes.

Brainy Fingertips

Edge-orientation processing in first-order tactile neurons. Pruszynski JA and Johansson RS. Nature Neuroscience, August 2014

A new study found that neurons in human skin are able to perform advanced calculations that scientists thought only the brain was capable of performing. A group of sensory neurons that extend into the skin and record touch are called first-order neurons in the tactile system. Each nerve ending branches in the skin to form about 5mm2 elliptical receptive field, with up to 8 highly sensitive zones that are unevenly distributed within the field. It turns out that these neurons not only transmit information about when and how intensely an object is touched to the brain, but they also send complex information about the touched object’s shape. Researchers found that the sensitivity of individual neurons to the shape of an object depends on the layout of the neuron’s highly-sensitive zones in the skin. Computations that require untangling geometric shape information are classified as feature extraction computations in neuroscience and are typically attributed to the immensely complex circuits of the cerebral cortex. This study showed that neuronal populations localized outside of the brain, such as first-order tactile neurons, can have advanced processing capacity similar to brain neurons. These results can also potentially improve treatments for nerve injury and rehabilitation, as scientists previously assumed that the cerebral cortex was doing all the work.

“The human brain, then, is the most complicated organization of matter that we know.”
Isaac Asimov

If someone asks what you recall when you look at the following pictures, I can hear you say ‘President Obama’ and ‘Statue of Liberty’. You just see a fragment of the pictures and remember them.

So, how does it happen? This is just a simple task for the brain. It stores an image and retrieves it whenever a part of it is seen. Amazing features of the brain, especially its power to learn and make decisions, inspires computer scientists in the field of artificial intelligence.

In computer science, an artificial neuron is a simple computational model of a neuron in the brain that excludes biological properties. Artificial neural networks (ANNs) are composed of artificial neurons, and they are utilized to solve specific problems, especially those that require learning and decision-making. ANNs may not be the best solutions in various machine learning problems; however, they are accepted as strong alternatives. Although ANNs don’t claim to be so, currently they are not even close to producing a simple model of the brain. Let’s take a short journey into the world of ANNs to experience the extreme difficulty of modeling the brain.

Some Applications of ANNs

Figure 1: Overview of ALVINN structure. Images obtained from the camera installed on the vehicle are provided to the ANN, and ANN decides the steering angle.

(adapted from: http://virtuallab.kar.fei.stuba.sk/robowiki/images/e/e8/Lecture_ALVINN.pdf).

ANNs have various applications in very large spectrum of problems that require learning, such as the Autonomous Land Vehicle in a Neural Network (ALVINN). The structure of ALVINN is shown in Figure 1. The ALVINN project by Carnegie Mellon University started in 1986 and aims to make a vehicle without a driver (Mitchell, 1997). In this project, ANN learns the steering habits of a driver. A camera is mounted on the vehicle to capture the images of the road. With respect to the continuous images provided, ALVINN determines the steering level with 45 different angle positions from sharp left to sharp right. Steering is updated 15 times per second so that it allows real-time control while driving at 55 mph. The system is trained by the data obtained from a human driver in a simulator and a real vehicle. ALVINN was able to speed up to 70 mph and successfully drive at 55 mph for 90 miles.

Figure 2: Handwritten zip codes (LeCun, et al., 1989)

Another example is handwritten zip code recognition (LeCun, et al., 1989). Zip codes from US Mail written by various people with large variety of styles and sizes were used in the experiments. Figure 2 presents some examples of zip codes in the experiment database. After the ANN was trained with more than 7,000 digits in the zip codes, it was 99% successful in recognizing around 2,000 digits in new zip codes.

Learning and Decision-making in ANNs

In order to understand the challenges better, we will first examine learning and decision-making in neurons and ANNs on simple examples.

Figure 3: (a) A typical neuron (adopted from http://commons.wikimedia.org/wiki/File:Neuron_-_annotated.svg), (b) artificial neuron in computer

Figure 3(a) illustrates a typical neuron which is the constituent of brain’s complicated network structure. Each neuron receives information as signals via dendrites, then evaluates it and generates a signal that is transmitted through its axon. A neuron has many connections between its dendrites and the axons of various other neurons. Figure (b) demonstrates an artificial neuron in computer science. It is considered a function: dendrites as the inputs of the function and generated signal via the axon as the output of the function.

Let’s see an example of an artificial neuron that understands if a given produce is a red apple or not. Think about how you understand whether a produce is a red apple or not. You see the shape and the color. However, it might be an artificial one for decoration. Then you can taste it and you get the sweetness of the apple. Similarly, our neuron receives three pieces of information as the input; ‘has circular shape?’, ‘is sweet?’, and ‘has red color?’. If the output is ‘yes’, that means the neuron recognizes the produce as a red apple. Otherwise, it will be ‘no’, which means the produce is not a red apple (Figure 4). Here, the neuron’s function is defined in such a way that it only generates ‘yes’ when all the inputs are ‘yes’.

Figure 4: Example inputs and outputs for the artificial neuron.

In an artificial neuron, some of the information can be more important than the others. For instance, to have red color may be more valuable in determining the price of produce. Assume that round shape and sweetness has equal value of $1; however, having red color is $2 – twice as valuable as the other features (Figure 5).

Figure 5: Artificial neuron with different input weights. Arrow thickness indicates the importance.

So, what is the big fuss about artificial neurons if they are only functions? In fact, the main feature of artificial neurons is learning. Considering the last example above, the neuron initially does not know the importance of the dendrites, i.e. the weights of inputs are all the same. If not trained, the neuron will generate the following answers which are sometimes wrong as indicated in Table 1.

Table 1: Artificial neuron before training; highlighted answers are wrong.

In real life, a teacher trains students. For instance, the teacher asks a question and if the received answer is not correct, she provides the right answer. Students learn the right answer and use this correct information in their lives. It is similar in artificial neurons as depicted in Figure 6. When the response of the neuron is incorrect, it adjusts the importance of the dendrites with respect to the correct answer hence it answers the same question correctly next time. During the training session, the neurons will be continuously asked the values of all the produce until it learns them all.

Figure 6: The learning process of the artificial neuron.

What if the problem gets complicated? Then one artificial neuron will not be sufficient, and we will need a network of neurons; ANNs. A more complex problem, ‘learning the digits’ is indicated in Figure 7.

Figure 7: (a) Digit learning problem, (b) ANN structure that learns digits. Due to the difficulty, only the connections between the input layer and first / last neurons in the middle layer are shown.

ANN has 3 x 5 = 15 input units like receptors of an eye retina. Each input unit corresponds to one square in the digits; either filled or blank. Each input unit is connected to the dendrites of all neurons in the middle layer. The output of each cell in the middle is connected to the dendrites of all neurons in the output layer. There are 10 output neurons corresponding to the digits from 0 to 9. After the ANN is trained, it provides a correct answer to the given digit as input. When digit ‘3’ is provided to the network, the neuron labeled with number ‘3’ in Figure 7(b) is triggered and outputs ‘yes’ whereas the rest of the neurons output ‘no’.

Figure 8: Faulty digit ‘3’ with a missing black square on the top right side.

Initially, all neurons in the network have equally weighted dendrites. After a reasonable amount of training, neurons adjust their weights, and ANN is able to identify digits. Here, we have some major challenges: what does ‘reasonable amount of training’ mean? When the ANN is undertrained, it will not always answer correctly to the digits given in Figure (a). In the other case, when the ANN is overtrained, it will memorize the digits provided during the training and will not recognize the faulty ones such as the one in Figure 8.

Challenges of ANNs

Beyond the mentioned the overtraining / undertraining problems, ANNs have a bigger challenge – how to determine the structure of ANN that fits the problem? In the digit learning example, we’re lucky because the structure is provided in Figure 7(b). However, the outcome of the solution may drastically depend on the number of neurons and the connections among them which is indeed a hard problem for ANNs.

The huge capability of the brain in learning and decision making comes from the huge number of neurons – around 100 billion – and the enormous amount of connections among them – from 100 to 500 trillion. The challenge to design such a huge network requires huge computation power. With the increasing number of neurons, ANN dramatically slows down especially during the learning process. Here, our example is a simple learning task of 3×5 pixel digits compared to the brain’s acquisition capacity of hundreds of images in our daily life. 

When the number of neurons gets larger, the reliability of network also reduces. Small adjustments in weights may change the entire behavior of the network hence it is easy to lose control of ANN. In contrast, the brain has a robust system, and its fault tolerance is admirable. Although neurons die every day, this doesn’t affect its performance significantly. The training method and how to update the weights are other hard problems leading to many different approaches in the neural computation field.

We have presented some simple tasks that can be solved using a few neurons and their challenges. On the other hand, consider the thousands of problems, various and incredible amount of information we have learned, and the thousands of decisions we make. The brain is truly amazing from the computer science perspective.

Bibliography

• Hertz, J. A., Krogh, A. S., & Palmer, R. G. (1991). Introduction To The Theory Of Neural Computation. Reading, MA: Addison-Wesley.
• Hopfield, J. J. (1982). Neural networks and physical systems with emergent collective computational properties. Proceedings of the National Academy of Sciences of the USA , 79, 2554-2588.
• LeCun, Y., Boser, B., Denker, J. S., Henderson, D., Howard, R. E., Hubbard, W., et al. (1989). Backpropagation applied to handwritten zip code recognition. 1 (4), 541-551.
• Mitchell, T. M. (1997). Machine Learning. McGraw-Hill.

Original article: Czupryn, A. et al., Science 334, 1133 (2011).

Neurons are a highly specialized group of cells that transmit electrical stimuli to elicit responses in the body. This high specialization comes with a price: with few exceptions, neurons cannot divide to replace nonfunctional ones. Over the past decade, cell therapy, that is treatment of a disease by introducing new cells, has emerged as a new hope for neurological disorders such as spinal cord injury, Alzheimer’s disease, and Parkinson’s disease, albeit with numerous challenges. One of the major problems in the field is to make the newly-introduced cells integrate into the neural circuitry of the host organism. This proof-of-concept study showed that it is possible for transplanted neurons to functionally integrate into the host brain and cure obesity in a specific genetic mouse model. This genetic mouse model lacks the ability to sense leptin, a hormone that regulates body weight and metabolism. Thus, these mice are prone to obesity and diabetes. The authors transplanted progenitor neurons isolated from the hypothalamus-a part of the brain that regulates numerous functions including metabolism, hunger and body temperature-of normal embryonic mice to the hypothalami of newborn diseased mice. Twenty weeks after the transplantation, cells were shown to be functionally integrated into the native circuitry. Integrated neurons were able to create electrical stimuli, transmit signals and, unlike the native neurons, respond to the hormone, leptin. Amazingly, transplanted mice were 30% lower in body weight and diabetes-free compared to the obese non-transplanted counterparts. The results were dramatic, despite the fact that only a few of the transplanted neurons were actually converted to the neurons that play a role in energy metabolism and leptin response. The authors explain this phenomenon by stating that the transplanted neurons may work as “antennas” to sense leptin and regulate other neurons in the native circuitry. Although current research is far from human application, it is still an important step towards treatment of detrimental neurological diseases.

2- A new record in solar cell efficiency

Original Article: Yella, A. et al., Science 334, 629 (2011).

Since their discovery in 1991, dye-sensitized solar cells (also known as Grätzel cells) have offered great potential despite their low efficiency values. They consist of dye-soaked titania nanoparticles coupled to an iodide-based electrolyte that allows for absorption of light and its conversion to electricity through the fast transport of electrons. According to a report in Science, researchers from ecole Polytechnique Federale de Lausanne (EPFL) have substantially improved the efficiency values over 12%, making this type of solar cells a feasible contender to the incumbent silicon solar cells. To store the most sunlight, these cells absorb the colors of the light spectrum with the highest energies and reject the rest such as the green light. In addition to the increase in cell efficiency, Grätzel and coworkers have also reduced their cost by replacing expensive ruthenium dyes with a zinc-based dye. Finally, they have improved the voltage output by using a cobalt electrolyte, a redox system that is more compatible than the previous iodide systems. This new system with improved components has also increased the theoretical maximum efficiency to 30%, which will require further optimization in device design and engineering to achieve. The only major drawback is the use of organic solvents potentially limiting the efforts for large-scale fabrication.

3- IQ can still change in teenage years

Original Article: Ramsden S. et al., Nature 479, 113 (2011).

Intelligence quotient (IQ) is a standardized measure of human intellectual capacity that takes into account a wide range of cognitive skills. IQ is generally considered to be stable across the lifespan, with scores at one time point being used to predict educational achievement and employment prospects in later years. However Prof. Cathy Price and colleagues have found that verbal and non-verbal IQ can rise or fall in the teenage years. They tested 33 teenagers-19 boys and 14 girls-in 2004, when they were 12 to 16 years old, and again in 2008, when they were 16 to 20 years old. Each time, the teens took IQ tests that measured their verbal and nonverbal abilities. Then, using magnetic resonance imaging, the researchers scanned the teenagers’ brains while they performed verbal tasks, such as reading or naming objects, and nonverbal tasks, such as solving visual puzzles with their hands. The idea was to match their test scores with a picture of their brain structure and activity at each time. The test results revealed dramatic changes between their first testing and their second: verbal and nonverbal IQ scores of participants rose or fell by as many as 20 points (on a scale with an average score of 100). Some teens improved or declined in either their verbal or nonverbal skills, while others improved in one area and declined in the other. The brain scans mirrored the score differences. For example, in teens whose verbal IQ scores had increased, the scans showed increased gray matter density in a region of the brain activated by speech. Teens whose nonverbal skills had improved showed changes in a brain region associated with motor movements of the hand. The authors note that these were the largest changes observed, and that there might be many more that were not noticed.

4- A coordination path from an infant’s heart to the mother’s heart

Original Article: Feldman, R. et al., Infant Behavior and Development 34, 569 (2011).

A group of researchers sat 40 pairs of mothers and 3-month-old infants face-to-face, equipped with sticky skin electrodes on either side of their hearts. Beat for beat, mother and child’s hearts thumped together almost instantly as they shared loving looks or contented coos. This cardiac coupling worked only for moms with their own babies, and only when the duos synchronized smiles and other cheerful social behaviors. The researchers suspect that when humans mirror each other’s facial expressions, they may switch on specific areas in the brain that tell the heart when to thump. Melding with mom lasts longer than just a few beats, however. Babies who don’t tune in with their mothers are less empathetic as teenagers, according to previous work from the same group. Premature infants or those whose mothers have postpartum depression may be most at risk for losing this social skill because they miss out on early opportunities to interact with their mothers. The authors state that future research is required to examine the impact of interaction synchrony on other physiological processes, such as hormonal release or brain activation.

Original Article: Wang, M. et al., PNAS (published online before print on March 1, 2010).

Periodic injections of insulin to manage blood sugar levels is critical for the treatment of diabetes patients. It requires continuous monitoring of glucose levels in the blood and multiple injections of insulin in order to mimic the natural balance of sugar-insulin levels in the human body. Yet, it is often difficult to maintain this extremely sensitive hormone balance without major side effects. These complications include blindness, leg ulcers and amputations, heart vessels problems, renal insufficiency, stroke, and nerve damage in the legs and arms. Moreover, the long-term use of insulin causes the increase of body fat and bad cholesterol. A new research study on non-obese diabetic mice shows that adding leptin- a hormone responsible for appetite control- to the insulin therapy results in better control of blood sugar levels and decreases the bad cholesterol and body fat of Type 1 diabetic mice. This is promising, as it could reduce heart and circulatory complications of Type 1 diabetes. However, the leptin therapy may not have an effect on type 2 diabetes, adult type, because in this type patients already have high levels of leptin. However, it has to be shown that leptin therapy is safe and effective on humans as well. There is a long way to go before we can use leptin in practical areas.

2- Re-teaching speech with music

Original Source: Schlaug G, Annual Meeting of the American Association for the Advancement of Science (AAAS), San Diego (2010).

Nearly 800,000 people in the U.S. are faced with strokes each year, and a quarter of those are affected by aphasia, a deficit in language. Using a new melodic intonation therapy, therapists treat patients by teaching them how to sing words and phrases consistent with the underlying melody of speech. As a result, the patients continue to speak in a more “sing-songy” way than a person with normal speech patterns, according to Dr. Schlaug, professor of neurology at Harvard Medical School. After 15 weeks, 1.5 hour-long daily sessions with a therapist, the patients gradually learn to piece the sung words together into organized speech. There are two separate brain networks associated with vocal output, with the one in the left hemisphere being engaged with speech and the other one in the right hemisphere strongly responding to music and melody. For the stroke patients that had damage to the left hemisphere, this therapy may help to train similar areas on the right hemisphere, helping them to initiate a speech region in the right hemisphere. Singing facilitates necessary engagement to the right hemisphere. Images of patients’ brains before and after the therapy reveal striking structural and functional changes in the right hemisphere. This study also reminds us of the brilliance of musical therapies employed in early hospitals in the Islamic world.

3- Renewable Jet-Fuels

Original Article: Bond, J.Q. et al., Science 327, 1110 (2010).

The global need for sustainable energy resources is ever increasing and the use of renewable fuels offer promising solutions. Among others, biofuels are especially important due to the presence of direct conversion routes from plant-based waste materials to conventional liquid fuels. However, high synthesis costs and complex processing steps are major hurdles to overcome before putting biofuels forward as economically viable alternatives to fossil fuels. Researchers are therefore trying to come up with more efficient methods -and one group, from the University of Wisconsin appears to have done so. Unlike commonly utilized routes involving microorganisms, they use a novel and environmentally-friendly chemical process which is easier to control and maintain. By using an inexpensive catalyst, they convert the majority of the wasted biomass to gaseous butene and carbon dioxide, with a water-based solution of gamma valerolactone as the intermediate chemical. The butene gas is then easily transformed to high-energy transportation fuels such as gasoline and jet fuel. As an added advantage, the stream of carbon dioxide can be efficiently captured, preventing the atmospheric release of this major greenhouse gas. Under optimized conditions, the system can operate uninterrupted for 90 hours with an overall efficiency of over 75%. Successful work like this will help make biofuels cheaper for mass production, pending the meticulous analysis of its economics.

4- Salt controversy: How much is too much?

Original Article: Bibbins-Domingo, K. et al., NEJM 362, 590 (2010).

Modern humans suffer from high rates of obesity (for instance, 64% of Americans are classified as either overweight or obese) and cardiovascular diseases, with the latter being the no.1 cause of all deaths. A recent study conducted by researchers at the University of California at San Francisco suggests that reducing dietary salt by half a teaspoon a day (~ 3g) would lower the annual number of new coronary heart disease, stroke and myocardial infarction cases. Strikingly, such a modest decrease is expected to decrease deaths from any cause by 44,000 to 92,000. According to the National Salt Reduction Initiative, Americans eat at least twice as much salt as they need where 80 percent of the salt in the American diet comes from processed or restaurant-prepared foods. However, eating too much salt is not a problem for people with healthy kidneys since kidneys are designed to flush out unneeded salt. However, when people have a high salt diet, then their kidneys are over-worked. Taking into account that modest salt reduction in one’s diet won’t likely cause harm and taste buds will likely adapt to this minor change effortlessly, it seems wise to refrain from using too much salt. This would trigger bigger health benefits ranging from not overworking the kidneys to reducing the risk of deadly diseases.

5- Why don’t we get thirsty during sleep?

Original Article: Trudel, E. & Bourque, C.W., Nature Neuroscience (published online before print on February 28, 2010).

In mammals, the “internal-standard-time” is kept by a particular subset of brain cells known as “clock-neurons” which display high activity during the day and low activity during the night. A group of scientists recently reported that the clock-neurons also function as a dimmer for water regulation, allowing bodily water content to be controlled by the body. A specialized group of cells, called osmo-sensory-neurons, detect and regulate water levels in the body, through balancing the water intake via thirst and loss via urine production. When water levels are low, the sensory-neurons communicate with some hormone-releasing cells which instruct the body to store water by ceasing urine production. By using isolated brain slices from rats, the researchers showed that the clock-neurons – when active – interfere with the communication between sensory-neurons and hormone-releasing-cells to suppress the water-storage-hormone release. In contrast, when the clock-cells are inactive (i.e., ‘sleep period’) the communication is restored, resulting in an increase of hormone levels to enable water-storage. Such regulation is the reason why we are not much disturbed during sleep by neither frequent trips to the bathroom, nor excessive thirst (that would both impair the sleep quality), and reminds us the verse from the Holy Qur’an: “..and He has made the night for rest…” (Chapter Al-Anaam, 96).

6- A passage to vegetative state through fMRI

Original Article: Monti MM et al., NEJM 362, 579 (2010).

Consciousness in medicine is defined as the patient’s alertness and responsiveness to the outside world. If a patient does not respond to external stimuli, his/her medical state is considered a “vegetative state”. Researchers from Cambridge, England performed functional magnetic resonance imaging (fMRI) experiments on 54 patients who had been previously classified as either “vegetative” or “minimally conscious”. Interestingly, 5 of 54 patients exhibited distinct neuronal activities in the corresponding regions of their brains, when they are given imaginary motor and spatial tasks. For the motor task, patients are asked to imagine playing a tennis game. For the spatial task, patients are asked to imagine navigating through a familiar location. A 22 year-old man who had been in coma for five months was further evaluated by being subjected to a simple set of yes-or-no questions such as “Do you have any brothers?” and was instructed to answer these questions using one type of mental imagery, that is a motor imagery for “Yes” and a spatial imagery for “No”. He answered 5 out of 6 questions correctly. This is the first evidence that through fMRI approach one can reach the residual cognitive activity in vegetative patients and establish functional communication, raising question marks about our current handling of these so-called vegetative patients.

The human ear and hearing

The human ear can be divided into several functional sections: the outer ear, the middle ear, the inner ear, and the auditory nerve. Sound goes through a series of changes as it travels through these sections until reaching the brain. The outer ear picks up sound pressure waves, amplifies them and then converts them into mechanical vibrations on the ear drum, which is connected to a series of small bones in the middle ear. These small bones further amplify or diminish the mechanical vibrations in the ear drum and transfer them to the cochlea, a snail-shaped cavity filled with fluid which is located in the inner ear. Change in fluid pressure caused by vibrations within the cochlea lead to changes in the flexible membrane, called the basilar membrane. These changes contain information about the frequency and strength of the sound that has entered the ear. Attached to the basilar membrane are mechanical receptor cells, called hair cells, which are bent according to the deflections of the basilar membrane.The hair cells have hair-like structures. The bending of these hairs assists the release of an electrochemical substance that causes neurons to send electrical signals to the brainstem through the auditory nerve. These signals are in the form of a message (or a code) that the brain understands.

Cochlear Implant (CI) devices

If there is a broken link in any part of the auditory pathway, the brain does not receive any coded signals, and hearing impairment occurs. If a large number of hair cells or auditory neurons in the cochlea have been damaged, then the person is diagnosed as profoundly deaf. The hair cells can be damaged by certain diseases (e.g., meningitis, Meniere’s disease), by congenital disorders, by certain drug treatments, or by other causes. One negative outcome of damaged hair cells is that they can subsequently lead to the degeneration of adjacent auditory neurons. Research has indicated that the most common cause of deafness is the loss of hair cells (>95%) rather than the loss of auditory neurons. This has encouraged scientists to try implanting a device inside the iner ear or cochlea, bypassing the normal hearing mechanism of the ear, to stimulate the remaining auditory neurons directly through electrical signals. These are called Cochlear Implant (CI) devices, which can restore partial hearing in profoundly deaf people . A standard CI system, shown in Figure 1, composes of and performs the following functions: a microphone picks up sound pressure waves and converts these into electrical signals. The signals are sent to the speech processor that is worn by the patient. The speech processor analyzes and encodes these sound signals, sending them back to the external pick-up coil . After passing through a wireless radio link that lies between the external and implanted coils and an implanted electronic devise, coded signals are sent to the implanted array of electrodes in the cochlea to electrically stimulate the remaining auditory neurons , and the brain receives what it interprets to be sound.

Electrical stimulation of the ear, or CI research, can be traced back to the 1800s. The Italian scientist Alessandro Volta used a battery as a research instrument to demonstrate that electric stimulation could result in a number of human sensations . After connecting a 50- volt battery to his ears, he noted that “…at the moment when the circuit was completed, I received a shock in the head, and some moments after I began to hear a sound, or rather noise in the ears, which I cannot well define: it was a kind of crackling with shocks, as if some paste or tenacious matter had been boiling…”. That electric stimulation of the auditory nerve provides hearing sensation in deaf people was reported more than 100 years after Volta . Electric stimulation in two deaf patients resulting in hearing was reported in 1957. These successes resulted in intensive research into helping deaf people hear in the 1960s and 1970s. One of the early successful single-channel CI devices was developed in the early 1970’s (3MCorp/House) and became the first commercially available CI device approved in the United States in 1984. The University of Utah developed a six electrode implant called the Ineraid or the Symbion device in the early 1990s. It was followed by other devices in Europe, the United States, and Australia.

The present status of Cochlear Implants

Today, around 10% of the population in developed countries suffers from hearing impairment. At present, the number of CI users has reached more than 100,000 worldwide, and is still growing rapidly. Functionally, CI has evolved from the single-electrode device that was used as an aid for lip-reading and

sound awareness to a modern, multielectrode device that can allow an average user to talk on the telephone. Even though significant technological progress has been achieved in the last 50 years, there are still many mysteries about the human hearing process and the parts of the ear. Here, we will compare some aspects of the healthy human ear and CI devices, looking to the future. The human ear operates over a range of sound pressures (its dynamic range) which is greater than one million to one (120dB), with as many as 200 discrete steps in the range. In contrast, today’s CI devices typically provide a dynamic range of three to one (10dB) to ten to one (20dB) with 20 discrete steps. This major difference is mainly due to the fact that the human ear is very adaptive in noisy environments, and is able to suppress noisy background, while picking up and processing appropriate sound signals for better perception. CIs do not differentiate between sounds, but amplify all sounds, which results in poor sound perception. Today, a typical multi-channel CI system uses 16 to 24 electrodes implanted in the cochlea with 8 to 22 signal processing channels. A potential shortcoming of having so many electrodes and channels in current CI technology is the electrical interference of electrodes during simultaneous electrode stimulation. These electrical interactions can disrupt the stimulus waveform prior to neural activity and degrade sound perception. The normal ear contains roughly 3,500 inner hair cells in the cochlea that are tuned to different frequencies from 20 to 20,000 Hz. They are connected to about 35,000 auditory nerves. Hair cells work as signal processing channels, yet each of the inner hair cells has also been wired in a sophisticated and little-understood fashion to 10-20 auditory nerve fibers that carry information to the central nervous system. Since they work in the chemical domain, they do not have the gross interference issues of CI electrodes. While good speech understanding has been achieved by users of modern multi-electrode CIs operating in quiet environments with 70–80% sentence recognition, allowing users to talk on the telephone, the CI devices do not discriminate between noise and the meaningful signals, only achieving speech understanding at between 70% and 80%, which falls to 10% or lower in noisy environments. It is a great challenge for CI users to appreciate music. Some CI listeners reported that they can enjoy music and are able to recognize melodies, but most described musicas sounding unpleasant and noisy, and performance could not be increased with current CI technology. CI users have difficulty in identifying differences in frequencies. Typically, they cannot discriminate any frequency difference for frequencies higher than 500 Hz, while the normal ear can hear up to 20,000 Hz with frequency discrimination between 2 to 3Hz at best. This gross difference is related to the issues surrounding signal processing strategies and electrodes of current CI systems. Predicting post-surgical performance based on presurgical conditions and tests of a CI candidate is still a problem for the physician. The cost of surgery is still high; in the United States, for example, a typical cost is between $40,000 and $75,000. Beyond these issues, the moral, cultural and ethical issues related to CIs are very complex. They are still debated, and are an important part of CI development in the world today. The hair cells in the human ear naturally deteriorate and die as we grow older. This process is typically sped up with exposure to loud noise. In common with all mammals, new hair cell generation in human ears stops right after the birth. However, in fish and amphibians, very similar cells are present and reproduce throughout life. Recently, it was found that hair cells of birds are repaired after being damaged by exposure to noise or ototoxic agents. It was also discovered that hair cells in the mammalian vestibular (balance) organ, very similar to those in the hearing system, can regenerate. These findings, along with other advancements in medical fields, lead to long-term research into different aids for hearing- impaired people. Despite the fact that hearing loss is usually permanent, scientists are optimistic that it may eventually be possible to reverse the damage in the ear by repairing or regenerating the sensory hair cells through gene therapy, stem cell transplantation, or ultimately by replacing the human cochlea with an artificial one. Today, Auditory Brainstem Implants are also being tried on humans for direct brainstem stimulation, bypassing the ears and the auditory nerves. Human beings and most animals on earth are born and equipped with a pair of ears for a good reason: having two ears enhances hearing and sound localization. Scientists are examining whether this is also true for deaf children who receive not one, but two CIs.

Conclusion

The sense of hearing is a gift for human beings which they hold dear and are grateful for, as much as for any of the other senses with which they have been equipped. It is important to strive to find cures for all kind of diseases, yet, more important than the cure is prevention of harm to our body and its amazing senses. Here, we have tried to open a small window onto human hearing, to examine how related impairments are being dealt with through cochlear implant (CI) devices, as well as looking at the issues related to these devices and the future directions of research for restoring hearing to deaf people. It is obvious that we have learned much about human hearing and ear in the past century; yet, this may well be just the tip of the iceberg.

References

1. S.U. Ay, F.-G. Zeng, B.J. Sheu, “ Hearing with bionic ear,” IEEE Circuits & Devices Magazine, Vol. 13, No. 3, pp.18-23, May 1997.

2. F.-G. Zeng, “Trends in cochlear implants,” Trends in Amplification, Vol. 8(1), pp.1-34, 2004.

3. A. Volta, “On the electricity excited by mere contact of conducting substances of different kinds,” Royal Soc. Philos.Trans., vol. 90, pp.403 431, 1800.

4. A.M. Andreev, G.V. Gersuni, A.A.Volokhov, “On the electrical excitability of the human ear: On the effect of alternating currents on the affected auditory apparatus,” Journal of Physiology USSR, Vol. 18, pp.250-265, 1935.

Statements like “God must have createdwith special care” are most inconvenientand disagreeable. Even for the mostsplendid things, God Almightycommands “Be! and it is.”

Imagine yourself in Spain, walking through the Alhambra palace. As you gaze at the artistry and beautiful architecture, you feel an urge to meet the master who built it. When you study other works of art, you see that throughout history, artists have used materials such as marble, iron, stones, wood, and glass, which are all found in abundance throughout our world, scattered in different places. The master architect however, uses the knowledge and willpower granted to him as it is represented in the spirit of a civilization. He transforms these things into living history. In other words, the physical structure and artistry of the Alhambra palace may stimulate a thinking mind to understand the whole of Andalusian civilization.

In the same way, imagine a clock. It is made of various parts: mills, springs, screws, etc. that are all made of materials like iron, nickel, and copper. Again, these can all be found in abundance around the world. An intelligent clockmaker uses these items as he accurately plans, calculates, and measures the correct number and placement of the mills, how they turn, their diameters, and other details that all require very sensitive adjustments. The mastery of craftsmanship contributes to the precision, and thereby to the value of the clock. Although the famous evolutionist Richard Dawkins claimed that such an accurate machine could be made by a “blind clockmaker,” I am compelled to grant the genius of accuracy with a little more respect to suggest that a precise clock requires the attention of a focused eye.

Just as with Alhambra and the clock, the genius of artistry and precision, when we perceive of the human being as work of art, we begin to understand the mastery that lies behind its development. Highlighting the amazing factual data about our physical and chemical structure, in this article, I try to find an answer to the question “what is a human being?” The resulting data reveals the degree to which human beings exist as magnificent works of art. My intent is to illustrate the intention of the Ultimate Master behind human existence.

Here are some basic facts about the approximate numbers, size, and longevity of our cells, the smallest living units in our body:

Facts in total numbers

Cells in a human body: 100 trillion

The variety of cells: 210

Cells dying every second: 50 million

Cells being created every second: 50 million

Red corpuscles: 25 trillion

White corpuscles: 25-100 billion

Neurons: 30 billion

(for a comparison, there are 100,000 neurons in the body of a fly and 10 million in the brain of a mouse)

Neurons in the brain cortex: 10 billion

Neurons in the cerebellar cortex: 10 billion

Synapses of all neurons: 100 trillion

Cells dying in a normal day: 50-100 thousand

Cells activated at a remembering process: 10-100 million

Cells producing gastric acid: male 1 billion, female 820 million

Size of sperms-the smallest cells: 3-5m (1 micrometer=10-6 m)

Size of glial cells in the brain: 5m

Diameter of egg cells-the biggest cells: 100-120 m

Average size of a liver cell: 30-50 m

Diameter of a red corpuscle: 7 m

Diameter of a kidney cell’s nucleus: 6.2 m

Chromosomes’ adjoined width at metaphase: 4.5 m

Diameter of the nucleus of a ganglion cell in the spinal cord: 1.2 m

Diameter of a mitochondria: 0.5-1.2 m

Diameter of a lysosome (enzyme carrier): 0.2-0.5 m

Microvilli on the small intestinal cells: 100nm (1 nanometer=10–9 m)

Diameter of a ribosome:12-20nm

Thickness of a cell membrane: 8.0nm

Diameter of a nexus on a cell membrane: 3.0nm

Diameter of a DNA double helix: 2.0nm

Length of an amino acid molecule: 0.8-1.1nm

Diameter of an atom: 0.1-0.5nm

Longevity of cells

Anal epithelial cells: 4.3 days

Epidermis cells: 19.2 days

Bowel epithelial cells: 10 days

Intestinal mucous cells: 1.4 days

Rectal mucous cells: 6.2 days

Bladder epithelial cells: 66.5 days

Lip epidermis cells: 14.7 days

Sole epidermis cells: 19.1 days

Tracheal epithelial cells: 47.6 days

Alveolar cells: 8.1 days

Gastric cardia epithelial cells: 9.1 days

Pyloric epithelial cells: 1.8-1.9 days

Inner ear epithelial cells: 34.5 days

Red corpuscles: 120days

Neutrophils: 4-5 days

Eosinophils: 10 days

Lymphocytes: 5 days to years

Monocytes: several months

Liver cells : 222 days

Kidney epithelial cells: 286 days

Thyroid epithelial cells: 287 days

Bone cells: 25-30 years

Neurons Lifelong

The cells which do not divide and reproduce:

Egg cells, brain cells, neurons, sweat gland cells, and hair papilla cells.

The human body is thus similar to a massive 3-D jigsaw puzzle; an incredibly complex one with trillions of minute-size pieces. It begins with a collection of 0.1 to 0.5 nanometer atoms that all come together to make up the elements of cells. From these elements-mitochondria and the like-a 100 trillion cells are formed that all come together to form the organs, muscles, tissue, and bones of the human body. All come together in a splendid fashion and all work together as if they are well aware of each other. All of this precision comes to together to form something that is both precise and beautiful.

This is not all. The process is renewed every second as cells wear out, die, and are reborn. In a few years, the body is an entirely new thing. Even more, the longevity of cells varies; some live only 1.4 days (intestinal mucous cells), while others last for months. Your body replaces cells at exact moments with perfect timing. No pause is allowed, and this is supposed to go on for some seventy years. It seems impossible to believe that such a thing can ever happen, that a “blind puzzle-maker” or any other chance-based mechanism could produce such a result. But here we are, living examples of beauty and precision. Somebody has already made us, didn’t He?