INTERACTION OF NEUROMODULATORY SYSTEMS IN MODULATING MEMORY STORAGE

An implicit assumption guiding many studies of neurochemical systems i nvolved in learning and memory in animal subjects is that animal and h uman memory systems use the same or similar mechanisms. Because acquis ition and retention performance can be influenced by many processes ot her than information storage, special effort is required to distinguis h influences on memory processes from other factors influencing perfor mance. This article reviews the findings of recent studies investigati ng the effects, on memory, of drugs affecting adrenergic, opioid pepti dergic, GABAergic and cholinergic systems. The review focuses primaril y on studies using posttraining treatments and tests for retention giv en no sooner than a day after the training. Extensive evidence suggest s that such drugs interact within the amygdaloid complex and that proj ections from the amygdala influence memory storage in other brain regi ons. The assumption that comparable processes occur in animal and huma n subjects is supported by evidence that in human subjects, emotionall y influenced memory is blocked by a beta-adrenergic blocker and by les ions of the amygdaloid complex.