Brain Science

Brain science MI muscle SI tactile combinations detection PA1 detailed actions for self SA1 tactile images DV2 spatial maps PA3 specific joint plans and DV1 spatial plan persons features PA4 overall plans Episodic memory Context PM1 person VI visual store Event map positions and G goals movements features PM2 person VV1 object actions and identities relations PM3 social dispositions and affiliations motor tactile visual input output input A theory of brain structure and function interacting selves, groups social psychology mental states, consciousness, the self psychotherapy cognitive mechanisms, motivation theories cognitive psychology system level brain models, neurocognitive models neuropsychology cortical layers, associative memory models neural nets single neuron models, synapses, transmission single neurons cell dynamics, synapse dynamics, genetic transcription cell dynamics by Alan H. Bond Brain Science A theory of brain structure and function based on neuroanatomy, psychology and computer science Alan H. Bond 1 September 20, 2004 1Alan H. Bond, Ph.D., California Institute of Technology, Computer Science Department, Mailstop 256-80, Pasadena, California 91125. email: [email protected] Disclaimer I started putting this book together on January 1st 2003, and now have a very rough draft. I will then rewrite it during the following months, guided by the criticism of a literary agent and potential publishers. This current version has a lot of mistakes and omissions, but it does outline what material will be in the book and in what order. There are currently many figures copied by scanning from other sources, but many of these will be redrawn by me. It is thus with due hesitancy that I am making it available so that it can help in ex- plaining my research. Any feedback and criticism is welcomed, please email me at [email protected] or phone me at 310-828-8719. To avoid a negative reaction to missing and incorrect details, it might help to think of it as a rough hewn sculpture rather than a detailed sculpture with errors. This is how I think of it. In the next months, I will be able to give it the necessary detail, precision, polish and completion. Quotation i Prologue from the PhD thesis of Paul D. Scott 1975 Sussex University, England, entitled “The cerebral neocortex as a programmable machine” ‘ THE PARADOX ‘It is conventional for a dissertation such as this to begin with a review of the current state of knowledge relevant to its subject. Unfortunately Sussex University possesses a library containing three hundred thousand volumes of which the vast majority are devoted to the subject matter of this thesis, the human cerebral cortex. Strangely only a small proportion of the authors concerned were actually aware that this was what they were writing about. Certainly many of those whose works are kept in the psychology section may have been but move a few shelves and we come to the astronomy section. Here we find expounded how the cerebral cortex has transformed the eye from an organ for finding the nearest meal into an instrument capable of perceiving the composition of a galaxy many millions of light years distant. Passing on a few feet we come to applied sciences. Here we can read how the hand-eye coordination which got our ancestors to the next branch has developed to enable men to get to the moon. Surrounding volumes describe innumerable ways in which the cortex by controlling our sensory and motor systems has developed ways of controlling the world. Wherever we go in the library we are confronted with testaments of cortical activity - in politics and economics, in mathematics and philosophy or in Marxism and theology. Take away the books and we still have the building as a consequence of activity in (among many others) Sir Basil Spence’s neocortex. Take away the building and we still have the concept of a library - an institution dedicated to fostering the most striking of all human cortical activities, verbal communication. No doubt many of our readers, whom we have so far ignored on our ’gedanken’ tour of the ii Quotation library (for fear of disrupting their cortical activities), would be horrified at such extreme reductionism. Such a reaction would not be possible without a cortex. It is impossible to avoid a feeling of awe upon the realisation that the whole of human achievement, so extensively documented in the history section is due to the organised firing of neurones in the neocortex. Nor should we make the mistake of attributing only the spectacular achievements of the human race to this region of the brain. We glance at the clock as we leave the library. It is five past one. Just time to skim through a chapter of a book before lunch. The cortex has translated a simple visual pattern into the concept of time and used this information to plan our future activities. Returning to our desks we open the book, a medical student’s introduction to the nervous system. What does it have to say about the neocortex? “There are essentially only two types of nerve cell in the cerebral cortex: a PYRAMID cell and a GRANULAR cell concerned with the output and input functions respectively. The pyramid cells have a long corticofugal axon and an apical dendrite which goes up to the most superficial layer of the cortex. The granule cells are characterised by a profuse dendritic tree while their axons are usually intracortical and so may go off in any direction. The neocortex is constructed in six layers. The outermost or MOLECULAR layer contains mostly the apical dendrites of the pyramidal cells together with a small number of internuncial neurones. The innermost or FUSIFORM layer contains internuncial and callosal neurons whose axons end in the most superficial layers of their own or the opposite side. The intermediate layers are made up as a four-decker sandwich of granular and pyramidal cells. Layers II and IV are the external and internal layers respectively while layers III and V are the external and internal pyramidal layers. The layers vary considerably in relative thickness in different areas of the cortex....” Bowsher (1970) This is of course an oversimplification. Nevertheless it is true that almost everywhere cerebral neocortex consists of a six-layered structure composed of a few basic cell types Quotation iii with definite, if not yet defineable, restrictions on their connectivities. So if we are to try and relate structure and function in the cortex we are at once confronted with a striking paradox. The cortex exhibits a uniquely diverse range of behaviour and yet it has a relatively uniform structure. Any attempt to explain how the brain works must sooner or later face up to this paradox’ Reference. David Bowsher, “Introduction to the anatomy and physiology of the nervous system”, 2nd ed. Oxford, Blackwell Scientific Publications, 1970. iv Quotation Preface v Style policy I and we. I have used I to mean Alan Bond alone, and we in two different senses, namely, we meaning the author and the reader, and we meaning the brain science community, the scientific community or people in general. Using I and my often sounds rather egotistical, but this is not my intention. The alternatives seem to be to either use we and our throughout, or to use reported speech, mainly passives. I noticed that other scientific books also use the mixed convention that I have adopted. The index. By inspection of preliminary forms of the index, I determined some categories which act as subheadings. Some of these are adjectives; I hope this makes sense. e.g., auditory, or even hierarchical. People’s names include their first name, unless it has been too difficult to find it, and I have not included middle initials, except to remove ambiguity. This is a little unusual in scientific writing, where often just the surname, or perhaps some initials as well, are used. It also becomes a problem when we get down to less important figures, where it is better to just use surnames alone. Also for teams of people, one can give the leader’s name and say “coworkers” or “their research colleagues”, or one can use the lead author’s name with et al. which can be misleading if the lead author is not one of the main scientists involved. I use lower case index terms unless they are proper names. I assumed that old world monkeys was all lower case. I have made hyphenation in the index consistent to avoid ambiguity, since in some contexts in the text we might need to hyphenate, but not in other contexts, but in the index there should be one corresponding form, e.g. context 1 - problem-solving method, vi Preface context 2 - problem solving, index entry - problem solving. There are a few ambiguous cases, for example joint rotation means a joint of one person rotating, whereas joint action means the action of two of more persons. A region only means the regions that I have defined as sets of areas. Other peoples’ regions I index as areas. Nuclei I also index as areas for now. I seem to have converged on orbital frontal cortex and not orbitofrontal cortex or orbital- frontal cortex. In any case, its abbreviation is OFC. Glossary. Since most of the terms used are defined and explained in the body of the text, it seemed that an explicit glossary would be wasteful. Instead, for every term used in the text I have made two index entries. One, under the term, I have put a subentry for its definition, and two I have put under an explicit index entry glossary with the term as a subentry.

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