Chapter 9: The Brain and Mind

 

If the brain is a component, is the entire nervous system a component? In general, we know that people have little problem with their nervous system, so the question is, is it capable of doing whatever is asked of it? Why is knowing how ‘robust’ the nervous system is, so important. The answer is that from the Mathematics of the Mind, the solution to patterns is the prediction, and the prediction requires that the underlying assumptions are robust enough to support the predictions.

 

‘7-31: the alpha motor system also routes most of its impulses through the cerebellum, where voluntary actions are integrated with information coming from the special senses and the proprioceptors.’ (JOB’S BODY, A Handbook for Bodywork, Deane Juhan, p 240) There is no part of the nervous system where activity is more brisk. There is not a sensory event in the body that is not evaluated, nor a motor event that is not monitored by the cerebellum. No signals originate here, but almost all pass through at one stage or another on their way to becoming behavior.’ (p 241)

 

A personal observation might be the best ‘proof’. As part of my anti-aging program and social scene I spend as much time as I can dancing Salsa, Rock’n’Roll, ballroom etc at a fast pace (and high level, I believe) with hyper-active young ladies. I find it very difficult to believe that someone of my age (70+ years) can do this with no problems, and at such speed. The point that I wish to make is that I do not know (consciously, that is) what moves I have done or what moves I will do. If I want to do a particular move, I hold it in my conscious mind and when dance and floor conditions allow it to be done, it will be done, unconsciously (not subconsciously, as will be explained later). Further, my field of vision only takes in the other dancers and the move is set in motion when it can be done so as to keep my partner out of other dancers way. It really is a strange experience!

 

There are few ladies that will move at that speed, but the few that do, like the complements that they receive! The point is that the two of us are doing separate steps, our hands are finding each others without fail and apart from navigating around the floor, we are part of the patterns of the music, the steps and each others movements, as well as avoiding the other dancers, all at top speed. This shows that the gamma system can handle whatever is thrown at it (provided that it is given time to grow the ganglions!). This ‘proof’ is a bit ‘rough’ but I am sufficiently satisfied with it to press on! Another example, is that I play the guitar in the classical way with the left hand fingering the strings, the right hand using five fingers to pluck the strings and the voice to sing the words of the song. The body is truly a marvelous machine, and does what is required of it, albeit with a lot of practice!

 

This example points to how animals (including us) function on a basic level. Our body moves as much as possible into an automatic system, leaving some part of the mind to always be able to make decisions, or in other words, to be conscious. Consciousness has been with organisms for a long time and the physics of it is explained in the next chapter.

 

Each animal obviously has within itself the ability to cope with change, otherwise it (and probably the species) is on the verge of extinction. This ability to adapt is a fundamental factor of life. It is why we have developed two sexes, it is ‘need it, grow it’, that it is the converse of ‘use it or lose it’, it is why species exist for long periods, and it leads animals, like ourselves to have to change. But we now have the chance to move to ‘Survival of the Best’ or risk dropping back into the ‘dog eat dog’ situation of Survival of the Fittest.

 

The thalamus ‘is a midline symmetrical structure within the brains of vertebrates including humans, situated between the cerebral cortex and midbrain. Its function includes relaying sensory and motor signals to the cerebral cortex, along with the regulation of consciousness, sleep and alertness.’ (Wikipedia, Thalamus)

 

‘The cerebrum is the newest structure in the phylogenetic sense, with mammals having the largest and most well developed among all species. In large mammals, the cerebral cortex is folded into many gyri and sulci, which has allowed the cortex to expand in surface area without taking up much greater volume…. The neural networks of the cerebrum facilitate complex behaviors such as social interactions, thought, judgement, learning, working memory, and in humans, speech and language.’ (Wikipedia, Cerebrum, Composition)

 

Using the Rule of Life, above, that body logic will be simple, the rule is also invoked by the body running two (or more) logical functions through the same organ. In the thalamus, I am concerned only with the relaying of sensory and motor signals to the cerebral cortex, at the moment). ‘The cerebral cortex is the layer of the brain often referred to as gray matter. The cortex (thin layer of tissue) is gray because nerves in this area lack the insulation that makes most other parts of the brain appear to be white. The cortex covers the outer portion (1.5mm to 5mm) of the cerebrum and cerebellum.’ (About.com, Education Biology, Cerebral Cortex, Regina Baily) ‘The living brain is very soft, having a consistency similar to soft gelatin or soft tofu’ (Wikipedia, Human Brain, Structure)

 

‘Because of its large number of tiny granule cells, the cerebellum contains more neurons than the rest of the brain put together, but it takes up only 10% of total brain volume. The number of neurons in the cerebellum is related to the number of neurons in the neocortex. There are about 3.6 times as many neurons in the cerebellum as in neocortex, a number that is conserved across many different mammalian species. The unusual surface appearance of the cerebellum conceals the fact that most of its volume is made up of a very tightly folded layer of gray matter, the cerebellar cortex. It has been estimated that, if the human cerebellar cortex were completely unfolded, it would give rise to a layer of neural tissue about 1 meter long and averaging 5 centimeters wide – a total surface area of 500 square cm, packed within a volume of dimensions 6 cm x 5 cm x 10 cm. Underneath the gray matter of the cortex lies white matter, made up largely of myelinated nerve fibres running to and from the cortex. Embedded within the white matter – which is sometimes called the arbor vitae (Tree of Life) because of its branched, tree-like appearance in cross section – are four deep cerebella nuclei, composed of gray matter.’ (Wikipedia, Cerrebellum, Anatomy)

 

‘From the viewpoint of gross anatomy, the cerebellar cortex appears to be a homogeneous sheet of tissue, and, from the viewpoint of microanatomy, all parts of this sheet appear to have the same internal structure.’ (Wikipedia, Cerebellum, Structure, Compartmentalization) ‘Prior to the 1990s, the function of the cerebellum was almost universally believed to be purely motor-related, but newer findings have brought that view strongly into question…. Kenji Doya has argued that the function of the cerebellum is best understood not in terms of what behaviors it is involved in but rather in terms of what neural computations it performs…. is best understood as a device for supervised learning, in contrast to the basal ganglia, which perform reinforcement learning, and the cerebral cortex, which performs unsupervised learning.’ (Wikipedia, Cerebellum, Function)

 

Bearing in mind the Rule of Life, the quotations above allow a ‘view’ of the body through time. Considering the nervous system only, from above, the ganglions in our spine (worm brain) are ‘boosted’ by the hind brain (lizard brain) is ‘boosted’ by the cerebellum (animal brain) and finally ‘boosted’ by the cortex (higher brain). Each of these ‘brains’ is composed of nerves and have come into being because of survival of the fittest. In the ‘higher’ brains (cerebellum and cerebral cortex), the memory and ‘switching’ devices are more visible. But first, let us look at ‘nerves’.

 

Other specialized glial cells – oligodendrocytes and Schwann cells – insulate the long axons with a tough , fatty coating called myelin. This insulation prevents signals from one axon inadvertently “leaking” into adjacent axons, and it also speeds up the passage of neural impulse considerably. Myelin is whitish in color, giving the so-called “white matter” of the nervous system its name. “White matter” contrasts to “grey matter” the color of cell bodies and axons that are not coated with myelin sheaths. (JOB’S BODY, A Handbook for Bodywork, Deane Juhan, pp 145-146)

 

This last paragraph is particularly important because firstly, this is another aspect of the Rule quoted earlier, where the body puts on enough of ‘something’ to enable the body to do what is required of it (the reverse of use it or lose it!). If we have to react faster to survive (where dance can be used as a substitute!), our body will increase the insulation around the nerves to speed up the impulses, as well as growing more ganglions. Secondly, the lack of insulation in the ‘grey matter’ points to, from above ‘signals from one axon inadvertently “leaking” into adjacent axons’. This is a case of the body using the nerves as in the reference to computers above, where there is stability with the myelin sheath to a form of chaos in the unprotected grey matter.

 

A number of references have mentioned gray matter (unshielded and, as seen in the next chapter, creating new thoughts) and white matter that is shielded and acts as normal insulated ‘wires’. Different parts of the brain contain a mix of gray and white matter and these are there for a reason, and I believe that that reason is that evolution produced a ‘set’ of ‘brains’, one on top of the other as the organism became more complicated. Gray matter produces creativity/consciousness and it is there at every level, and is heritable!

 

In the beginning, nerves evolved to control and synchronize the movement of muscles so that the organism could move around. The next sense to evolve was probably that of smell because it is connected directly to (what is now) the forebrain. This can be clearly seen in a schematic of the brain of a fish. (Wikipedia, Fish, Central nervous system)

 

‘These persistent biochemicals penetrate the mucus and brush against little quill-like protein receptors that stud the nerves in the olfactory epithelium. The receptors can recognize a large number of smell-evoking molecules… the neurons begin to fire excitedly … to a group of nerves lying directly above them, in the olfactory bulb…. every other sensory system, at this point, must send a signal to the thalamus and ask permission to connect to the rest of the brain – including the higher levels where perception occurs…. one of those destinations is the amygdala … because smell directly stimulates the amygdala …. smell directly stimulates emotions. Smell signals also head through the piriform cortex to the orbitofrontal cortex, a part of your brain just above and behind your eyes and deeply involved in decision making.’ (Brain rules, John Medina, p213)

 

Consider ‘the receptors can recognize a large number of smell-evoking molecules’ from above. This is as would be expected, and is the first attempt at a ‘brain’. Two nostrils provide the direction for the creature to move so that the intensity is equalized, and a large number of receptors to define ‘alluring’ smells and to define a ‘scale’ of desirability. A simple hard-wired system that is still with us.

 

Consider ‘the neurons begin to fire excitedly’. At this early stage of evolution, the ‘brain’ consisted of nerves throughout the body, including those directing the muscles, and the olfactory neurons (one on each side) would have guided the creature to the food. The continuous firing guided the animal. But the body runs on an inhibitory versus excitatory system, with the neurotransmitters providing the balance of desirability. This is how balance is attained, from a logical point of view, to make the body into a ‘computer’.

 

Then at some point, eyespots evolved. But, ‘serviceable image-forming eyes have evolved between forty and sixty times, independently from scratch, in many different invertebrate groups’ (River Out of Eden, Richard Dawkins, p 91) Eyespots evolved to register change from one state (of what is being observed) to another, so that the appropriate action can be taken. The only way this could be done is to have the nerve impulses from the eyes be put into a register and held till the next sampling comes in and is compared to it. Then, at the next sampling time the original is overwritten, and so forth. Where could this happen?

 

‘How do we cram the vast universe of our experience into the relatively small storage compartment between our ears? We do what Harpo did: we cheat…. it is compressed for storage by first being reduced to a few critical threads. Later, when we want to remember our experience, our brains quickly reweave the tapestry by fabricating – not by actually retrieving – the bulk of the information that we experience as a memory’ (Stumbling on Happiness, Daniel Gilbert, pp 78-79)

 

‘The cerebral cortex is the newest portion of the nervous system, and in man it has developed into the largest portion. In its anatomical connections, it is clearly an outgrowth of the areas of the brain directly beneath it- the hypothalamus’. (JOB’S BODY, A Handbook for Bodywork, Deane Juhan, p 173) ‘London is a taxi driver’s nightmare, a preposterously large and convoluted urban jungle built up chaotically over some fifteen hundred years…. In order to be properly licensed, London taxi drivers must learn all of these driving nooks and crannies – an encyclopaedic awareness known proudly in the trade as ‘The Knowledge’…. In contrast with noncabbies, experienced taxi drivers had a greatly enlarged posterior hippocampus … the longer the driving career, the larger the posterior hippocampus…. These data,’ concluded Maguire dramatically, ‘suggests that the changes in hippocampal grey matter … are acquired’. (The Genius in All of Us, David Shenk, pp 29-30)

 

I believe that the body contains a number of ‘computers’, and the easiest to explain is the amygdala, hippocampus, thalamus and cerebral cortex system, because it is the largest and most recent. ‘Computation’ occurs where there is grey matter, and it is present, from above, in the hippocampus and the cerebral cortex. The thalamus is, I believe, a switching device that increases the efficiency of creative thought. The hippocampus contains the ‘registers’ that store the ‘memories’, which are a set of impulses from the body’s sensors, for comparison at future times.

 

‘The brain’s amygdala aids in the creation of emotions and our ability to remember them.’ (Brain rules, John Medina, p250) This is a simple statement of, I believe, the main function of the amygdala, which is to assign an emotional label to each input from our sensors. Those elements with a high emotion attached, such as escaping a predator, finding a new area of food, remembering the social order of members of the herd are held in a register within the hippocampus. Those inputs with a low emotional attachment are forgotten.

 

Firstly, how do the nerves work. ‘6-17: Not only must fluid be free to circulate around a neuron, fluid must flow all the way out its long axon and back again in order for the life of the cell and the conditions for action potential propagation to be maintained. Nerve cells are as hydraulic as they are electrical.’ (JOB’S BODY, A Handbook for Bodywork, Deane Juhan, p 156) ‘6-14: Each action potential ripples down the surface of the axon. The advancing internal positive charge continues to open more sodium (Na+) gates. Once a local area beneath the membrane has achieved a positive charge, this charge closes the Na+ gates and opens K+ gates, expelling K+ from the cell and restoring the net negative charge. This creates the rippling motion of the action potential along the axon. It then takes about four more milliseconds for the cell to re-establish the original ionic balances, setting the trigger for the next action potential. During this time, the membrane is refractory, and cannot generate another action potential.’ (p 153)

 

‘At the synapse, where the axon of the first cell joins to the dendrite or the body of the next cell in line, this polarity reversal causes the quick release of a neurotransmitter. The most common neurotransmitter seems to be acetylcholine, although there are a number of other important ones. Once released into the synaptic cleft, this acetylcholine contracts the membrane of the next cell, with dramatic effect: the membrane, which at rest had been sixty to seventy times more permeable to potassium than to sodium, suddenly becomes six hundred times more permeable to sodium. The sodium gates are thrown open, and a volume of positive sodium ions rushes into the cell, making the interior region immediately beneath the synapse positive (+30 mV.) instead of negative (-70 mV.). The acetylcholine is immediately reabsorbed by the first cell, to be reused for the next stimulation, but the disturbance of the polarities it triggered continues along the membrane of the second cell in a self-perpetuating ripple.’ (p 152)

 

‘Grey matter’, is the term used for nerves without insulation, and these nerves have an external positive charge that tends to keep them apart. Further, ‘as neurons learn, they swell, sway and split. They break connections in one spot, glide over to a nearby region, and form connections with their new neighbors. Many stay put, simply strengthening their electrical connections with each other, increasing the efficiency of information transfer. (Brain rules, John Medina, p57)

 

The biological computer described above, shows two construction simplifications (compared to the manufactured computers that we all use). Firstly, action potentials are propagated at a constant voltage, no matter what the distance along the nerve, and secondly, new connections that are created, carry the same action potential regardless of the number of new connections. This effect of a biological computer greatly simplifies the maintenance of voltages throughout the system.

 

Further, ‘this conduction and transmission of action potentials is the only functional activity of our neurons. Their collective circuitry forms the fastest communication system within the body. Impulses ripple across their surfaces at an average of two hundred and fifty miles an hour, a speed which makes their traverses of the body very nearly instantaneous.’ (JOB’S BODY, A Handbook for Bodywork, Deane Juhan, p 155

 

So, the pulses travel from the sensor (or senses) and those with higher emotional (or importance) labels are held in ‘registers’ in the hippocampus. Thus the hippocampus is a storage area that sorts the important memories from those that are unimportant and can be discarded. So, how could the ‘strings’ of potentials be held for the long-term? ‘The hippocampus is relevant to memory formation for more than a decade after the event was recruited for long-term storage. After that, the memory somehow makes it to another region, one not affected by H.M.’s brain losses, and as a result, H.M. can retrieve it.’ (Brain rules, John Medina, p140) H. M. is a patient with hippocampus damage.

 

Thus the simplest means of forming a ‘register’, using the above, is to have a nerve transmit permanently (for up to ten years) a slowly moving (250 miles per hour) string of action potentials in a continuous loop. This simple system is expensive in energy, in order to keep the action potentials moving, and is backed up by the following. ‘The brain’s appetite for energy is enormous. The brain represents only about 2 percent of most people’s body weight, yet it accounts for about 20 percent of the body’s total energy usage – about 10 times more than would be expected.’ (p 20) If this idea is correct it points to another case of inefficiency that has evolved, and that we must accept.

 

It also appears, from above (the taxi drivers) that the hippocampus can hold vast amounts of information. Also, ‘if we take the two hippocampi to consist of roughly 10 power 4 networks of 10 power 4 neurons each, then their storage capacity is (using a Hopfield net estimate) approximately 10 power 11 bits, which is quite large, given Landauer’s estimate that we acquire only about 10 power 9 bits of information in a lifetime.’ (Memory and Dreams, George Christos, p70) . However, from above, this information is also processed before being retained with an emotive label. Thus the hippocampus is a computer, good enough to navigate the streets of London, but this is just the start!

 

‘The cerebral cortex is the layer of the brain often referred to as gray matter. The cortex (thin layer of tissue) is gray because nerves in this area lack the insulation that makes most parts of the brain appear to be white. The cortex covers the outer portion (1.5mm to 5mm) of the cerebrum and cerebellum…. The cerebral cortex consists of folded bulges called gyri that create deep furrows called sulci. The folds of the brain add to its surface area and therefore increase the amount of gray matter and the quantity of information that can be processed…. It encompasses about two-thirds of the brain mass and lies over and around most of the structures of the brain…. The cerebral cortex is divided into lobes that each have a specific function. For example, there are specific areas involved in vision, hearing, touch, movement and smell. Other areas are critical for thinking and reasoning. Although many functions, such as touch, are found in both right and left cerebral hemispheres, some functions are found in only one cerebral hemisphere.’ (Cerebral Cortex, Regina Bailey, About.com Guide) ‘Cognitive and volitive systems project fibers from the cerebrum to the thalamus and to specific regions of the midbrain. (Wikipedia, Cerebrum, Composition)

 

The important points from the above are, I believe, the cortex encompasses about two-thirds of the brain mass, it is uniform in structure and is composed of gray matter and contains lobes that each have a specific function. The thalamus is, I believe, simply a switch to transmit the parts of a memory into different areas (lobes), so that each lobe contains information relevant to vision, hearing, touch, movement etc. The cortex is a computer because of the gray matter and any ‘result’ of thinking would be (essentially) random if the thalamus did not organize the information into lobes. The thalamus creates better ‘association’ in creative thinking. For example, a sound in the night would target the sound lobe that would generate other memories of sounds in the night. The time has come to put forward the method by which I believe the brain ‘thinks’, and that will be done in the following chapter.