Cellular and network mechanisms of hippocampal -prefrontal coordination during memory consolidation (360G-Wellcome-204761_Z_16_Z)

Consolidation of newly acquired memories takes place during sleep and involves the interaction of hippocampus and prefrontal cortex. The cellular mechanisms and synaptic pathways underlying this process are not fully understood but it has been hypothesized that synchronous hippocampal ripples and prefrontal cortex spindles mediate it. The present project proposes a multimodal approach to investigate these mechanisms in rodents. The first goal will be to dissect the fine-scale dynamics of memory reactivation in hippocampus and cortex during sleep after learning of a spatial memory task. This aim will be achieved with simultaneous large-scale recordings in both structures and advanced analysis of population activity. The second goal will be to unveil which anatomical regions and synaptic pathways are mediating this inter-regional synchronization. Simultaneous electrophysiological and functional magnetic resonance recordings will be performed in sleeping rats before and after the task and wide-brain activity will be assessed at times of high hippocampal-prefrontal synchrony. The last goal will be to causally verify the participation in inter-areal coordination and memory consolidation of the key synaptic pathway(s) pointed out in the previous stage. To achieve this, closed-loop optogenetic silencing of specific cellular populations would be performed at times of hippocampal-prefrontal synchrony during sleep memory consolidation.