crick, francis
<p>Francis CRICK  died in 2004  WHILE editing the Claustrum paper... he was 88 and still working hard.
 
 
 
Jan 7, 2009 8:48 PM
 
1.3 Crick's astonishing hypothesis about consciousness has four main ingredients:
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<p>In what Crick calls his Processing Postulate, he argues that each level of visual processing is coordinated by a single thalamic region, thus making the <b>thalamus</b> a key player in consciousness (p. 249).
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<p><b>Consciousness and short term memory need the activity of reverbratory circuits to maintain them</b>.
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<p>In the case of the primary visual cortex (V1) <b>there are 5 to 10 times more fibres going back to the thalamus from layer 6 of the cortex than those coming to the entire visual cortex from the thalamus. Crick argues that it is these interconnections which provide the basis for the reverbratory circuits.</b>
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<li>Awareness requires the activity of the various cortical areas as well as the thalamus, which raises a problem in that the major visual area of the thalamus (the Lateral Geniculate Body) projects almost solely to V1. Thus if layer 6 is so vital to consciousness in its interactions with the thalamus, where do the layer 6's of higher visual areas, such as V4 and V5, do their interacting with the thalamus? Crick suggests that the Pulvinar nucleus might be a site but the evidence indicates that its projections to higher areas are not strong.</li>
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<p>Here's what Christof has to say about Francis...
We worked for almost twenty years. When I moved from MIT to Cal Tech in '86 we started to interact and we met on a monthly basis to talk about the brain, and then in 1989 he started becoming very intensely interested, because there was a certain neurobiological discovery -- we became very interested in that and we thought maybe this would be one of the critical features -- a signature of consciousness in the brain.
Some were very smart, some were very perceptive, some were not so, some were just crazy, but you know, you have this fantastic person, this creative genius, who can just throw out these ideas, and he wants a sounding board to tell him, well, this isn't going to work, this is really great but this is totally silly, and really have a give or take over many, many hours. That was his style of working, that you came in the morning and from ten o'clock 'til six o'clock you would just discuss papers, he would go through the evidence, he would sift the data, discuss it, look at it from different light, reject it, have a hypothesis, reject it again, then dinner, and then usually after dinner that process would continue. He kept this up 'til essentially the day he died.
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