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Since this is a book about the brain, I thought it was necessary to discuss the fundamental aspect of its structure. However, I only laid a gross picture with broad strokes only after briefly discussing the highlights of the history of evolution of the brain. Then I tried to address some of the big questions like the consciousness and the generation of the mind and self from a neurological point of view. I went ahead and discussed the mechanism of some of the attributes of self as well.
Some of the functional aspects are elucidated as how we fall in love or how we navigate directions and so forth. Computation is the basis by which the brain derives its conclusions. The plasticity of the brain enables us to learn new skills. The genetic aspect cannot be overemphasized. I have included some fascinating data that has recently been found out in these regards.
Psychiatric illnesses always fascinated me. I have discussed the genetic basis and pathophysiology of a few of them, like Depression, Alzheimer's disease, etc.
The whole book is written on the basis of the latest findings by dedicated professionals. Here I am like a collector who has put all this in a concise deliberation to share my own understandings regarding what it takes for each of us to be the way we are.
Unlocking the Enigmatic Brain
Francis Creek, the father of DNA and a Nobel Laureate of 1962 said, "You, your joys and sorrows, your memories and your ambitions, your sense of your personal identity and your free will are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules." This is why, in the context of 'know thyself', it has been the quest of many to try to understand how the brain makes it all possible. The intricacy of the brain is to be appreciated to realize that there is no single approach available to explain it all. An attempt to explain can only be made in increments, bit by bit striving to gain an understanding of what actually transpires in the background that translates into a perception or a behavior.
The only life that has been mapped with all its neural connections is a tiny worm called C. elegans. It has a humble nervous system comprising 302 neurons. Scientists meticulously studied this small creature in the 70s and 80s and mapped all the connections of those neurons, 7000 in all. In that map, the lines drawn showed the connection and the nodes were neurons. Although it was supposedly a simplistic scenario, yet it looked like a complex maze. However, it should not be too difficult to realize that the firing patterns in those circuitries translate into the behavior of this worm. It gets increasingly harder as we move up the life forms. A tiny piece of a living brain containing ten thousand neurons roughly approximates to 1% of the brain of a cockroach. If we magnify it to a million times, we will find that it exhibits a pattern with random neurons turning on and off in different locations continuously, which poses a challenge that our brain cannot readily comprehend. The human brain's activity is a hundred million times more complicated than that. Somewhere in those patterns in each of us lie all our perceptions, emotions and thoughts, ideas and beliefs, memories and plans for the future. So it has become essential for the neuroscientists to take aid of supercomputers to simulate the pattern that arise out of inputs in the form of mathematical deliberation representing each individual neuronal activity embedded within a given network. A host of these formulae containing variable data collectively generates a pattern that represents the behavior of that network. This can be a whole lot easier to comprehend as this can be manipulated.
A fresh brain has a pinkish-gray gelatinous structure, with red (arterial) blood vessels coursing all over its grooves. Its consistency is somewhere between hard jelly and cold butter. Under naked eyes, it does not reveal any complicacy. Only when we look through an electron microscope and zoom in a hundred thousand times at high resolution, we begin to see the neurons, which are the nerve cells. As we turn the resolution even higher, we see the intricacies of their connections. Some may have seen a picture of a neuron, perhaps of some artist's simplified rendition. In reality, they resemble more like large trees with the ramification of branches ending in twigs. A variety of neurons connected in a grid like network each having its own intensity of firing collectively accomplish the automated or intended functionalities that in turn gives rise to either a perception or a behavior. In order to see all the connections of a neuron we have to include a great many neurons at the same time. A great many neurons connected together in a network are evident even in a cubic millimeter as can be seen in the cortex. Networks can also be traversing a huge area of the brain.
Nerves pretty much do one thing only and that is they communicate. It is probably a common knowledge that this communication is carried out through electrical signals. This communication takes place in a language or code, which is essentially a non-physical logic. This code thus can be expressed mathematically. The variation of output takes place due to the variability of the value of the parameters. For a better understanding of this code, let us consider any sensory system. Photons of light on entering the eyes stimulate the production of electric signals that eventually reach the Primary Visual Cortex in the back of the head and beyond to the higher centers. These centers coordinate the input while processing to generate a unified perception of vision ultimately. However, at the beginning of that process, each color that enters the eyes generates a unique code, which is embedded in a series of impulses produced by the retinal cells that comprehensively represent the information about that particular color at the pertinent centers of the visual cortices. Our eyes can encode a million colors having a unique code for each. Likewise, signals travel through our Olfactory nerve carrying information about what we smell and these are all non-physical, purely logical codes as well. Moreover, the signal for smell have further variations that enable us to tell the difference between a burning tire and a second hand cigarette smoke, just like a certain signal means blue and a certain other means green and so forth in our vision. One set of signals carries the precise feeling of touch, another carries the taste in our mouth, another for the sounds we hear. Signals in the form of code transmit our reasons or emotions; some signals carry the intra-brain communication while others, the operations of the body. Coded electrical signals traverse billions of neurons for the purpose of creating our thoughts.
Each one of the billions of nerve cells creates a precise amount of electricity that it uses to transfer its particular code. The nerve cells create the electrical signals by sending sodium and potassium ions in and out of the cell wall at rates varying up to 1000 exchanges per second. In 1/1000th of a second, the cell changes from a negative charge to a positive charge only to revert back in the next 1/1000th. In this way, nerve cells "hum" with electricity. However, the entire electric output does not exceed 20 watts, which is even less than some of the refrigerator bulbs. This includes the noise produced by the near misses at the synapses, which fails to contribute to the spike. Thus, the brain is a machine that does its work not by meticulous precision but by an abundance of over activity as the neuron is bombarded with incoming spikes. Each neuron by generating its spike, contribute to the behavior of the network it is connected to. Our perceptions are nothing more than electrical signals traversing the sensory receptors having originated from a sensory organ.
It is in the pattern and the speed of the hum that the brain transfers data and creates our thoughts. Each neuron, having received signal from upstream through a chemical messenger at its multiple synaptic locations, evaluates the combined signal to determine the state of the threshold. If that is achieved, it immediately passes the signal downstream by releasing its chemical messenger at the other end. The neuron with its myriads of branches and twigs connects with thousands of other neurons through these synapses, usually having more connections on its upstream than the downstream. The neuron is thus actually an electrical device. The electricity that they generate, travel through the pathways of least resistance, following the property of electricity. This is facilitated by the neuronal connectivity, which has been laid down genetically. However, they can be modified with our experiences. It can be explained by observing the water running through a creek. As the creek facilitates the passage of water, the water also shapes the creek in course of time. It is also interesting to note that the codes conveyed through electrical signals actually have no physical resemblance to which they convey through their specific pathways. It cannot care about the overall content as the overall content is always beyond any single neuron along the pathway. Collectively they make sense.
The chemical messenger released at the nerve endings are of immense importance. Their rise and fall affects our mental experience as well as the traits in our personalities. Their efficacy is governed by the transporter molecules, which are expressed by our genes. The efficacy also depends on the receptors on the receiving terminal, abundance or scarcity of which creates a remarkable difference. The efforts to mitigate such difference lead to synaptic plasticity, thereby the overall plasticity of the brain.
There are tens of thousands of different types of neurons. Some of those have recently been discovered raises the notion that there might be much more that are waiting to be discovered. Although genetically they belong to the same group as nerve cells, having different switches turned on and off within their genes allow them to show different properties and actions thereby. Thus, some are excitatory, that readily charge up their neighbors while others are inhibitory, that quieten their neighbors and so forth. Malfunctions of certain cells, called the basket cell, have been associated with Schizophrenia. Simultaneous hyperactivity of excitatory cells in some area of cortex leads to bouts of epilepsy and that has long been known. Why certain microscopic locations make some people prone to an illness like these, while some other areas get affected in case of others producing similar consequences, is not clearly understood.
The research scientists have the tools to look into the mouse brain or a tiny chunk of human brain altogether. They make thin slices of the frozen brain by a glorified meat cutter. After fixing the slide, they zoom in on them and color code the twigs of neuron(s). When they stack up these slices and strip away everything else but the color-coded areas, they see the pattern of the twig in 3D with the aid of the current state of computer processors. If there are two twigs present in the slide, they follow along to see the pattern of synapses in the eventual 3D models with a concurrent simulation on their giant monitor to contribute to the process of creating the map. Then each of these stacks is only 0.6 microns thick meaning it represents a very tiny chunk of the mouse's brain. Although the mouse's brain is ten thousand times smaller than the human brain, it is a mammal and the intricacies of its neural connections very much resemble our own connectivities. Besides, the mouse brain is more readily available than the human brain. However, it is the human brain that we seek to understand and studying the mouse brain is related to understanding the processes of our own brain.
Behaviorally, how the brain exhibits our intrinsic properties are no less complex. Come to think of the critic we all have within ourselves. It may take up the role of a religious leader or a mother in her absence or the ego for those among us who are rather Freudian. This may arise from our own conscience but reserve the potential to act as an independent de novo based on circumstances. It is created out of the teachings of life each of us receives out of the environment we grow up in that again extends into our culture. It is mostly what our mothers instill in our heads while we are too young which we usually forget, but their ramified expressions reserve the potentials to surface when need be. The critic within not only may criticize our actions; it can even reprimand us afterwards. It can torment us and in some extreme cases can even be fatal. It can nudge us with urgings in a subtle way to be better in whatever we choose to do. As we are inherently imperfect, that is why striving towards achieving perfection in whatever we do is the essence of our lives.
To understand how brain mediates self-awareness is mind boggling as is. It may almost seem like trying to go to the moon on a bullock cart. Then if we twist the dimension of mind further by adding an independent critic to it, that really can throw us off that bullock cart altogether. However, the human spirit is all about trying to gain an understanding. Thus, research projects are underway in the hundreds of facilities around the world. The standard mode of operandi is mostly studying the animal models where there is a correlation. A complete comprehension of this neural code is a prerequisite that may serve as the stepping-stone to begin to understand the human brain in the ultimate way.
Certain Algae as they arise from the deep in the ocean possesses a property that the genetic engineers have developed their fancy about. As the Algae approach the shallow depth of waters containing sunlight, they open certain gate made of protein to draw in the energy from sunlight as a stream of electricity that enable them to perform their daily chores, like digestion. These charged particles, once having crossed the threshold, causes bio-luminance. Scientists extracted their genes after having identified the responsible ones that lead to the bio-luminance, they inserted them into a rat's neuron, which acted as if being infested by a virus. The part of DNA, thus incorporated, installed those photosensitive protein receptors on the surface of the neuron, which then began to glow in the dark in response to a blue light being flashed on them. These bio-luminance techniques are the mode of future to identify a group of cells within a network isolating them from the rest to observe their functionality or treat them when they become corrupted without affecting the rest of the brain. Industrial scale researches are being conducted to gather a broad understanding of scopes like these.
Repetitive tasks or repetitive thoughts or emotional feelings must arise from the repetitive expression of identical codes. These patterns are easier to isolate in the maze. However, once all the neural codes are broken, that can lead to opening the Pandora's Box. Eventually machines will appear that can calibrate itself real fast to collect data out of a customized unique brain like the ones any of us have. Once that takes place, memories can be uploaded, thoughts can be transferred live real time, beliefs can be transplanted and so forth. It will be a whole different world out there then. A new kind of database will be required to evolve to accommodate the classified collections of a mind. If the human race continues onward to see that day without blowing up everyone to oblivion with its stockpile of arsenals, it will lead to a lifestyle we cannot think of yet, whether or not we live to see that day. So establishing the code of ethics is imperative as the science progresses to respect the expectations of the society.
We are now living in a fascinating time, having the human genome mapped and cataloged. Now we clearly understand why someone's eyes are blue while someone else's green. However, our genomic expression is not just skin-deep. The headlines say, genes can give us illnesses, shape our personalities and mental disorders. Our genes seem to have awesome power over our destinies. Yet we all are more than our respective genes. That idea comes from the environmental penetrance on genetic manifestations. Nevertheless, the genes govern the scope of neuronal behavior, which in turn shapes us who we are.
Now one can have a realistic hope that soon will be the day, a supercomputer will assimilate inputs from a fleet of powerful microscopes into a real time 3D rendition with resolution reaching desirable magnitude for magnification purposes. We need to learn how to deconstruct and reconstruct the brain in simulation to have the real understanding of it. That will answer for the last time if we are just our neural connections or there is something else to it. For now, there seems no way there can be anything else other than the patterns of connections in our respective brains.
Excerpted from The Enigmatic Brain Reveals by Dewan Jaglul. Copyright © 2013 Dewan Jaglul. Excerpted by permission of AuthorHouse.
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