Phantoms in the Brain: Probing the Mysteries of the Human Mind Read Online Free PDF Page B

information except smell passes through it before reaching the outer cortical mantle. Interposed between the thalamus and the cortex are more nuclei, called basal ganglia (with names like the putamen and caudate nucleus). Finally, on the floor of the thalamus is the hypothalamus, which seems to be concerned with regulating metabolic functions, hormone production, and various basic drives such as aggression, fear, and sexuality.
    These anatomical facts have been known for a long time, but we still have no clear idea of how the brain works.6 Many older theories fall into two warring camps—modularity and holism—and the pendulum has swung back and forth between these two extreme points of view for the last three hundred years. At one end of the spectrum are modularists, who believe that different parts of the brain are highly specialized for mental capacities. Thus there is a module for language, one for memory, one for math ability, one for face recognition and maybe even one for detecting people who cheat. Moreover, they argue, these modules or regions are largely autonomous. Each does its own job, set of computations, or whatever, and then—like a bucket brigade—passes its output to the next module in line, not "talking" much to other regions.
    At the other end of the spectrum we have "holism," a theoretical approach that overlaps with what these days is called "connectionism." This school of thought argues that the brain functions as a whole and that any one part is as good as any other part. The holistic view is defended by th fact that many areas, especially cortical regions, can be recruited for multiple tasks. Everything is connected to everything else, say the holists, and so the search for distinct modules is a waste of time.
    My own work with patients suggests that these two points of view are not mutually exclusive—that the brain is a dynamic structure that employs both "modes" in a marvelously complex interplay. The grandeur of the human potential is visible only when we take all the possibilities into account, resisting the temptation to fall into polarized camps or to
    ask whether a given function is localized or not localized.7 As we shall see, it's much more useful to tackle each problem as it comes along and not get hung up taking sides.
    Each view in its extreme form is in fact rather absurd. As an analogy, suppose you are watching the program Baywatch on television. Where is Baywatch localized? Is it in the phosphor glowing on the TV screen or in the dancing electrons inside the cathode−ray tube? Is it in the electromagnetic waves being transmitted through air? Or is it on the celluloid film or video tape in the studio from which the show is being transmitted?
    Or maybe it's in the camera that's looking at the actors in the scene?
    Most people recognize right away that this is a meaningless question. You might be tempted to conclude therefore that Baywatch is not localized (there is no Baywatch "module") in any one place—that it permeates the whole universe—but that, too, is absurd. For we know it is not localized on the moon or in my pet cat or in the chair I'm sitting on (even though some of the electromagnetic waves may reach these locations). Clearly the phosphor, the cathode−ray tube, the electromagnetic waves and the celluloid or tape are all much more 14

    directly involved in this scenario we call Baywatch than is the moon, a chair or my cat.
    This example illustrates that once you understand what a television program really is, the question "Is it localized or not localized?" recedes into the background, replaced with the question "How does it work?" But it's also clear that looking at the cathode−ray tube and electron gun may eventually give you hints about how the television set works and picks up the Baywatch program as it is aired, whereas examining the chair you are sitting on never will. So localization is not a bad place to start, so long as we avoid the pitfall of thinking