The human cerebrum is divided into two hemispheres, the right and left. These sides are not identical to one another in structure or function. The right hemisphere is in charge of coordinating functions related to the left side of the body, and the left part of the brain controls the right side of the body. To date, science hasn’t been able to explain the reason for this split.

There are other differences between the hemispheres, including functions like speech and motor skills. For example, in 90% of people, speech and hand skills are centered in the left hemisphere. However, skills such as drawing, architecture, or sense of perspective – skills that are spatial and dimensional – are dominated by the right hemisphere. While the two hemispheres are employed for various tasks, they communicate with each other. For this to happen, a structure called the corpus callosum, which contains only axons as nerve extensions, is placed between the two hemispheres and enables the transfer of information. For instance, if a needle sticks your left hand, this is perceived by the right hemisphere. In patients where the corpus callosum is missing or disconnected, when an image of a red apple is shown with the left eye closed and again with the right eye shut, the patient will report having seen no apple.

The lack of a corpus callosum is rarely encountered as a birth defect (corpus callosum agenesis). In this instance, there is rarely a deficiency when it comes to movements and sensory receptions. Activities such as speaking, standing, balancing, walking and running are almost similar to normal levels.

In the case of epilepsy, an abnormal electric current is observed in the cerebrum. The corpus callosum can be cut by surgery, disconnecting the two hemispheres in order to prevent the dispersal and transfer of abnormal electricity to the other hemisphere of the brain.

These days, this surgery is not implemented unless necessary. Obviously, performing this surgery means communication between the two hemispheres is interrupted; the tasks that are assigned to the right brain remain only in the right and the ones assigned to the left brain stay in the left. This can complicate basic motor skills. For instance, if a person wants to write or throw a ball with two hands, this task is first planned in the left hemisphere, then it is transferred to the motor-skill regions found in both hemispheres via the corpus callosum. These skills are developed via both sides of the brain and our hands, and usually one hand is better in these skills than the other. Because the left brain is usually dominant, most people are right handed.

Schizophrenia is a permanent psychiatric disease that affects a person’s emotions, thoughts, and behaviors. It means being split-minded, or the separation of the mind (in Greek, schizo means split, or divided, and phrenos means mind). In schizophrenia, the coordination between the hemispheres is disrupted and the two hemispheres intervene simultaneously to solve the same problem. Briefly, it may not cause a problem if a specific task requires only one hemisphere to be in charge; however, complications arise when both hemispheres try to solve the same job. In schizophrenic patients, it has been reported that a problem exists in the corpus callosum; therefore, communications are hindered between them. This results in a disruption.

At this point, some questions may arise. Why is our body controlled by two brain regions that have different jobs? Why do these two hemispheres communicate? What would happen if our brain was not built in two parts?

It’s hard to give answers to these questions. Sometimes, we end up with nothing to say but, “if God creates in this way, then it must be in the most beautiful form.” There is nothing useless, extra and unnecessary in the human body. But the following can be hypothesized regarding the two sided functioning of the brain: cerebral hemorrhages always occur in only one side of the brain. Speech is lost if the left side is injured, and spatial and geometrical skills are lost when the right side is injured. Therefore, maybe while a function is lost on one side, the functions of the other side are conserved.

Though the different hemispheres of the brain are in charge of different functions, they successfully fulfill their duty to activate our bodily functions through constant communication. Despite continuing clinical studies, the full extent of the brain’s power remains mysterious. Its incredible design, which allows the body to function so perfectly, is a sign of humanity’s remarkable architecture.

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.

In the early 1970s, a young graduate student, Richard Blakemore, observed an interesting group of bacteria in a mud sample collected from Eel Pond in Massachusetts. These bacteria were migrating through a certain edge of the microscope slide. Rotating the slide did not affect their motion; they were still moving through north. Repeating the experiment in the dark also showed that it was not light that affected the bacteria’s swimming direction. The experiments left one possible explanation to the directed motion of the bacteria and that was a crazy one-that they were sensing the magnetic field of the earth! It wasn’t hard for Blakemore to place a magnet next to the microscope slide and to prove that the crazy idea was indeed true. The bacteria were attracted by the south pole of the magnet and repelled by the north pole of it. This was the beginning of a new field of an interdisciplinary research, which attracted many scientists from very different fields such as, microbiology, physics, geophysics and paleogeology.

To understand how magnetotactic bacteria feel the magnetic field, it would be useful to check one’s transmission electron micrograph (Figure 1). The chain of magnetite (iron oxide) crystals forming a specialized organelle, called magnetesome, can be seen easily. The length of the whole chain is around one micron and each small crystal is around 50-60 nanometers. Each small crystal can be considered as a small magnet. These small magnets are aligned in a way that they support each other and the chain becomes a strong magnet. A lipid bilayer membrane surrounds this chain and holds them together. Forming chains on a straight line is not an expected behavior for small magnetite crystals. If they are produced synthetically, they accumulate together to form an aggregate. The pathways of chain formation in magnetesome are still an open question.

Magnetotactic properties are not limited to a certain species. There are many different bacteria that have magnetotactic properties. Therefore the magnetesomes may differ in size, length and even in chemistry. Some magnetotactic bacteria have greigite (iron sulfide) minerals instead of magnetite. Alsothere are magnetotactic bacteria that have more than one magnetesomes. (Figure –2)

Magnetesomes passively align bacteria parallel to the geomagnetic field but do not exert a force on bacteria to change their speed. Aligned with the magnetic field, the bacteria decide to either move towards south or north. Interestingly, almost all magnetotactic bacteria in northern hemisphere are north seeking, almost all magnetotactic bacteria in southern hemisphere are south seeking, and magnetotactic bacteria living around the geomagnetic equator consist of almost equal number of bacteria of each magnetic polarity. The bacteria in northern and southern hemispheres may have different polarities but they have one thing in common; they both move downwards. The geomagnetic field is not exactly parallel to the earth’s surface except around the geomagnetic equator. As it may seem in figure-3, the magnetic field lines are tilted up and down respectively in southern and northern hemispheres. Therefore the north seeking bacteria in northern hemisphere end up at the bottom of the water and so do the south seeking bacteria in southern hemisphere. Most of the magnetotactic bacteria cannot survive in atmospheric oxygen levels, so sensing vertical position and moving downwards, where oxygen concentration is low, is crucial for them.

Being north seeking or down seeking, i.e. polarity, is a genetic property for magnetotactic bacteria. Almost all progenies (descendants) of a north-seeking cell are also north-seeking cells. However this requires partition of magnetesomes to each daughter cell during the division. Occasionally, daughter cells may have no magnetesomes or they maybe too small to have a magnetic moment, so they develop their own magnetesomes. When these progenies develop their own magnetesomes they may have either polarity. Therefore any natural population of magnetotactic bacteria has less than 0.5% “wrong” polarity members. Wrong is written in quotation marks because without that “mistake” magnetotactic bacteria would live only in one hemisphere of the earth.

Magnetotactic bacteria are not the only creatures that can sense geomagnetic field. For example birds, also, can sense geomagnetic field and find their direction while they are migrating. However, birds use other factors such as sun and the horizon to find their direction and their body is much more complex. Also they do not sense magnetic field in a mechanical way like magnetotactic bacteria do, but probably they have some complex chemical ways of magnetic reception. That is another research field by itself and this article’s volume is not enough to go into it.

Everything, every entity that we see around us calls us to reflect upon their Creator. The ones that we see with electron microscopes or high-tech tools are not exceptions. Magnetotactic bacteria synthesizes magnetite crystals from scratch and then puts them in an order like beads hitched on a string. Could it be possible for them to manage this incredible task on their own accord and without acting in the name of God? To this day we cannot even understand the basic principles of that process to its complete degree in order to mimic it. In fact, the more we understand the more we esteem and at awe we become from the great craft of Supreme Artist.

Auroras (northern lights), with their beautiful colors, make long winter nights more bearable in Arctic Circle. They are emitted by charged particles, something very harmful for living creatures if ever reached to earth’s surface and trapped in earth’s geomagnetic field. (Figure-4) While thinking about magnetotactic bacteria I remember those beautiful scenes I had seen in pictures that had caught my awe and wonder and can’t help but express deep gratitude once more to the Creator and Sustainer of it all, of us all, who guides the tiny little cells to more livable environments with the very same geomagnetic field that He protects us from harmful solar winds. Extraordinary is the ordinaries we are surrounded by!

Ahmet Uysal is a PhD candidate in Physics at Northwestern University, Evanston, IL.

References

1. Richard P. Blakemore, 1982, “Magnetotactic bacteria”. Ann. Rev. Micrbiol. 36:217-238
2. Dirk Schüler, 2008, “Genetics and cell biology of magnetesome formation in magnetotactic bacteria”. FEMS Microbiol. Rev., 32:654-672
3. Arash Komeili, 2007, “Molecular mechanisms of magnetesome formation”. Annu. Rev. Biochem. 76:351-366
4. Thorsten Ritz, Salih Adem, and Klaus Schulten, 2000, “A model for photoreceptor-based magnetoreception in birds”. Biophysical Journal. 78:707-718
5. http://www.birdgeo.com/images/CTE1810.jpg
6. http://solar-center.stanford.edu/images/solar-wind-magfield_b.gif