Cellular mechanisms of memory consolidation
Final Report Abstract
Overall, we have shown that the perirhinal projection to L1 of neocortex is crucial for learning a cortical and hippocampal dependent µStim learning task that involves the emergence of distinct neuronal subpopulations marked by burst firing, correlated with an increase in their dendritic Ca+2 activity. The fact that perirhinal input to neocortical L1 is also crucial for memory formation but not for sensory perception, suggests that perirhinal input to the apical dendrites serve as a gating signal for the enhancement of these long-range, cortico-cortical contextual inputs. The data presented in this study therefore imply that medial-temporal-dependent learning predominantly involves the plasticity of cortically-driven, contextual information, which would have ramifications not only for our understanding of the brain but also for the principles of learning in artificial recurrent networks. In summary, we show that the medial temporal input to the neocortex enables memory formation via a process in L1 that enhances dendritic Ca+2 activity of distinct L5 excitatory subpopulations and promotes burst firing in these, serving as the neural signature of memory in the neocortex.
