| First Author | Malik R | Year | 2022 |
| Journal | Cell | Volume | 185 |
| Issue | 9 | Pages | 1602-1617.e17 |
| PubMed ID | 35487191 | Mgi Jnum | J:328750 |
| Mgi Id | MGI:7266585 | Doi | 10.1016/j.cell.2022.04.001 |
| Citation | Malik R, et al. (2022) Top-down control of hippocampal signal-to-noise by prefrontal long-range inhibition. Cell 185(9):1602-1617.e17 |
| abstractText | Prefrontal cortex (PFC) is postulated to exert "top-down control" on information processing throughout the brain to promote specific behaviors. However, pathways mediating top-down control remain poorly understood. In particular, knowledge about direct prefrontal connections that might facilitate top-down control of hippocampal information processing remains sparse. Here we describe monosynaptic long-range GABAergic projections from PFC to hippocampus. These preferentially inhibit vasoactive intestinal polypeptide-expressing interneurons, which are known to disinhibit hippocampal microcircuits. Indeed, stimulating prefrontal-hippocampal GABAergic projections increases hippocampal feedforward inhibition and reduces hippocampal activity in vivo. The net effect of these actions is to specifically enhance the signal-to-noise ratio for hippocampal encoding of object locations and augment object-induced increases in spatial information. Correspondingly, activating or inhibiting these projections promotes or suppresses object exploration, respectively. Together, these results elucidate a top-down prefrontal pathway in which long-range GABAergic projections target disinhibitory microcircuits, thereby enhancing signals and network dynamics underlying exploratory behavior. |
