Monday, January 07, 2008

Hippocampus, theta waves and movement

I've been reading another book about this topic, An Odyssey Through the Brain, Behavior and the Mind, by C.H. Vanderwolf, found by following a trail from the Buzsáki book I was absorbed in all fall, Rhythms of the Brain. I will bring a summary of info here, direct from this book, about which behaviors with which Vanderwolf found theta rhythm associated and those he didn't. But first, an introduction:

Vanderwolf was born and raised in rural Alberta which provided him much opportunity to observe animals in nature, on his way to becoming one of the world's foremost theta rhythm researchers. This book is the story of his research, partly autobiographical but mostly about what he discovered, and includes a defense of his anti-"mentalist" stance in research on behavior. In the 1964 he began his own research on rhythmical hippocampal activity. He says (p.3):
"The program of research that I had in mind was based on certain philosophical presuppositions. Most investigators in the brain-behaviour field, both in 1964 and at present, assume that the ultimate problem for neuroscience is to provide an explanation of the human mind. More specifically, this is usually taken to mean discovering the neural basis of consciousness and its subprocesses such as perception, attention, memory, cognition, emotion, motivation, etc. I was very suspicious of this entire enterprise and gradually came to believe that the traditional categories of the mind did not provide a valid natural subdivision of different brain functions."

He wanted to approach research from nature's own direction (p. 4):
"During my career as a student, I had taken several laboratory courses in mammalian physiology, pharmacology and biochemistry and had been much attracted by the idea that a living animal can be regarded as an enormously complex machine whose operations are all potentially explicable in physical and chemical terms. Most of the brain, it seemed to me, was dedicated to the control of motor activity (behavior). If the entire forebrain and midbrain are surgically removed from an animal (leaving an island of the hypothalamus to permit operation of the pituitary gland), respiratory, cardiovascular, digestive, and excretory functions proceed almost normally but spontaneous behaviour is abolished. Such a decerebrate animal can no longer walk about, feed itself, groom itself, seek shelter, avoid enemies, find a mate, or care for its young. Therefore, it must be that what the intact brain does is generate all of these (and more) varied behavioural performances. To say that a decerebrate animal has no behaviour because it is unconscious seemed to me to be no explanation at all but merely a restatement of the problem in more obscure terms."

No comments: