The reason for asking is that normal brains go through a "pruning" process in the toddler years and later with the onset of adolescence. I have been to several conferences in which speakers have stated that the pruning process (i.e. rate of neural loss) was much greater than one percent a year - that in fact it is rather extensive, and, moreover is actually a means by which brains become more efficient. No one seems to know why pruning makes brains work better -though in information theory terms a reduction in "noise" would enhance their information processing capacities. As a corrolary, it is possible that due to a neoteny "spillover" process, nature slowed human development so much that our brains get too big and require streamlining along the way. If, as the study suggests, schizophrenia goes beyond the pruning process it makes one wonder if, like the runaway growth of cancer cells, some sort of "runaway pruning process" unchecked by whatever time regulator genes typically push the start and stop buttons of brain development might be involved in schizophrenia. I wonder if there is any research in that regard? One final comment about an extremely interesting study. Why do drugs work with schizophrenia - often times restoring virtually if not completely, the normal associative capacities of the person afflicted? If schiz is not primarily a biochemical disorder but is also some function of massive tissue damage it might force us to view the brain according to the holistic - or even holographic models proposed early on by Lashley and later by Pribram. It is common knowledge that there is not a very strong correlation between amount or location of brain tissue and cognitive or perceptual functioning, but the question remains: what combination of tissue mass, neurotransmission, perhaps slow potential wave functions produce the kinds of cognitive, speech and perceptual skills of normal people - and just as intriguing, can one or more of these features be used to compensate for a weakness in the others? Hopefully research along this line will continue, thuogh one suspects it will not only provide facts but raise a number of theoretical questions.
The UCLA study is interesting, not just because of what it implies about causation but also what it implies about brain function. One confusing item (perhaps it was the wording) had to do with the percentage of cortical(?) tissue that is destroyed in the teen years. On one hand the study says 10 percent is detroyed in schizophrenic teens and that one percent a year over a seven year period is destroyed in normals. Is this in fact a comparison between 7 percent and 10 percent over the same period? Or did the study indicate that there was a 10 percent loss of brain tissue in one year - or a shorter period of time for the schizophrenic group?
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