Self Comes to Mind

of organized movement. 1
    Maps are also constructed when we recall objects from the inside of our brain’s memory banks. The construction of maps never stops even in our sleep, as dreams demonstrate. The human brain maps whatever object sits outside it, whatever action occurs outside it, and all the relationships that objects and actions assume in time and space, relative to each other and to the mother ship known as the organism, sole proprietor of our body, brain, and mind. The human brain is a born cartographer, and the cartography began with the mapping of the body inside which the brain sits.
    The human brain is a mimic of the irrepressible variety. Whatever sits outside the brain—the body proper, of course, from the skin to the entrails, as well as the world around, man, woman, and child, cats and dogs and places, hot weather and cold, smooth textures and rough, loud sounds and soft, sweet honey and salty fish—is mimicked inside the brain’s networks. In other words, the brain has the ability to represent aspects of the structure of nonbrain things and events, which includes the actions carried out by our organism and its components, like limbs, parts of the phonatory apparatus, and so forth. How the mapping happens exactly is easier said than done. It is not a mere copy, a passive transfer from the outside of the brain toward its inside. The assembly conjured by the senses involves an active contribution offered from inside the brain, available from early in development, the idea that the brain is a blank slate having long since lost favor. 2 The assembly often occurs in the setting of movement, as noted earlier.
    A brief note on terminology: I used to be strict about using the term image only as a synonym of mental pattern or mental image, and the term neural pattern or map to refer to a pattern of activity in the brain as distinct from the mind. My intent was to recognize that the mind, which I see as inhering in the activity of brain tissue, deserves its own description because of the private nature of its experience, and because that private experience is precisely the phenomenon we wish to explain; as for describing neural events with their proper vocabulary, it was part of the effort to understand the role of those events in the mind process. By keeping separate levels of description, I was not suggesting at all that there are separate substances, one mental and the other biological. I am not a substance dualist as Descartes was, or tried to make us believe he was, by saying that the body had physical extension but the mind did not, as the two are made of different substances. I was simply indulging in aspect dualism and discussing the way things appear, on their experiential surface. But, of course, so did my friend Spinoza, the standard-bearer for monism, the very opposite of dualism.
    But why complicate matters, for myself and for the reader, by using separate terms to refer to two things that I believe to be equivalent? Throughout this book, I use the terms image, map , and neural pattern almost interchangeably. On occasion I also blur the line between mind and brain, deliberately, to underscore the fact that the distinction, while valid, can block the view of what we are trying to explain.
Cutting Below the Surface
     
    Imagine holding a brain in your hand and looking at the surface of the cerebral cortex. Now imagine taking a sharp knife and making cuts parallel to the surface, at a depth of two or three millimeters, and extracting a thin filet of brain. After fixing and staining the neurons with an appropriate chemical, you can lay your preparation down on a thin glass slide and look at it under the microscope. You will discover, in each cortical layer that you inspect, a sheathlike structure that essentially resembles a two-dimensional square grid. The main elements in the grid are neurons, displayed horizontally. You can imagine something like the plan of Manhattan, but you must leave Broadway out because there are no major oblique lines in the cortical grids. The arrangement, you immediately realize, is ideal for overt topographical representation of objects and actions.
    Looking at a patch of cerebral cortex, it is easy to see why the most detailed maps the brain makes arise here, although other parts of the brain can also make them, albeit with a lower resolution. One of the cortical layers, the fourth, is probably responsible for a large part of the detailed maps. Contemplating a patch