PROTEIN-KINASE-C IN THE HIPPOCAMPUS IS ALTERED BY SPATIAL BUT NOT CUED DISCRIMINATIONS - A COMPONENT TASK-ANALYSIS

The exact role of the mammalian hippocampus in memory formation remain s essentially as an unanswered question for cognitive neuroscience. Ex periments with humans and with animals indicate that some types of mne monic associative processes involve hippocampal function while others do not. Support for the spatial processing hypothesis of hippocampal f unction has stemmed from the impaired performance of rats with hippoca mpal lesions in tasks that require spatial discriminations, but not cu ed discriminations. Previous procedures, however, have confounded the interpretation of spatial versus cued discrimination learning with the number and kinds of irrelevant stimuli present in the discrimination. An empirical set of data describing a role of protein kinase C (PKC) in different mnemonic processes is similarly being developed. Recent w ork has implicated the activation of this serine-threonine kinase in a variety of learning paradigms, as well as long-term potentiation (LTP ), a model system for synaptic plasticity which may subserve some type s of learning. The present study employs the principles of component t ask analysis to examine the role of membrane-associated PKC (mPKC) in hippocampal-dependent memory when all factors other than the type of l earning were equivalent. The results indicate that hippocampal mPKC is altered by performance in hippocampally-dependent spatial discriminat ions, but not hippocampally-independent cued discriminations and provi de a general experimental procedure to relate neural changes to specif ic behavioral changes.