Projections from neocortex mediate top-down control of memory retrieval.
| Publication Type | Academic Article |
| Authors | Rajasethupathy P, Sankaran S, Marshel J, Kim C, Ferenczi E, Lee S, Berndt A, Ramakrishnan C, Jaffe A, Lo M, Liston C, Deisseroth K |
| Journal | Nature |
| Volume | 526 |
| Issue | 7575 |
| Pagination | 653-9 |
| Date Published | 10/05/2015 |
| ISSN | 1476-4687 |
| Keywords | Memory, Neocortex, Neural Pathways |
| Abstract | Top-down prefrontal cortex inputs to the hippocampus have been hypothesized to be important in memory consolidation, retrieval, and the pathophysiology of major psychiatric diseases; however, no such direct projections have been identified and functionally described. Here we report the discovery of a monosynaptic prefrontal cortex (predominantly anterior cingulate) to hippocampus (CA3 to CA1 region) projection in mice, and find that optogenetic manipulation of this projection (here termed AC-CA) is capable of eliciting contextual memory retrieval. To explore the network mechanisms of this process, we developed and applied tools to observe cellular-resolution neural activity in the hippocampus while stimulating AC-CA projections during memory retrieval in mice behaving in virtual-reality environments. Using this approach, we found that learning drives the emergence of a sparse class of neurons in CA2/CA3 that are highly correlated with the local network and that lead synchronous population activity events; these neurons are then preferentially recruited by the AC-CA projection during memory retrieval. These findings reveal a sparsely implemented memory retrieval mechanism in the hippocampus that operates via direct top-down prefrontal input, with implications for the patterning and storage of salient memory representations. |
| DOI | 10.1038/nature15389 |
| PubMed ID | 26436451 |
| PubMed Central ID | PMC4825678 |