There is a fair amount of evidence that the brain structures that mediate associative learning are different from those that mediate storage of declarative memories. Generalizing from fear conditioning and associative learning about places in mazes to retention of verbal memories may be too large a leap.
Something that selectively knocks out the contribution of the amygdale to encoding memories with strong negative emotional components might bridge the disruption of fear conditioning and PTSD-type intrusive memories related to trauma, but the mediating mechanism would (I suspect) have to be specific to amygdale function and might not generalize to other types of learning or memory encoding. See: Squire, L. R., Knowlton, B., & Musen, G. (1993) The structure and organization of memory. Annual Review of Psychology, 44, 53-95. Claudia Stanny (2) Perhaps long-term memories of conditioning are purely mediated by PKMzeta in rodents and maybe it applies to some limited cases of conditioning in humans but it is unlikely to be plausible for many/most human long-term memories. The classic "levels of processing" experimental result showing that processing a word's appearance results in poorer memory than processing its meaning is clearly a problem if one relies upon a molecular mechanism or a single neuron mechanism (the problem is similar to that for the classic "grandmother" or "yellow volkswagen" account of pattern recognition). At the very least, a neural circuit is needed and perhaps a more complex neural network is needed if one is going to rely on purely associative mechanisms in contrast to general rule and symbol architectures. -Mike Palij New York University [email protected] --- To make changes to your subscription contact: Bill Southerly ([email protected]) --- To make changes to your subscription contact: Bill Southerly ([email protected])
