Given the assumed pivotal role of the medial entorhinal cortex (mEC) in controlling hippocampal activity, I examined whether and how optogenetic silencing of the mEC affects hippocampal sharp wave ripples (SPW-Rs). SPW-Rs are population bursts in the hippocampus that generally occur during Non-REM sleep, and are precisely coordinated with neocortical sleep states, playing an essential role in cortico-hippocampal memory consolidation.
I found that mEC silencing reduced SPW-R occurrence, altered their spike content and suppressed their relationship with neocortical UP-DOWN states. These results suggest that a main role of mEC is to select neuronal assemblies of SPW-Rs and temporally coordinate their occurrences with neocortical events (Zutshi & Buzsáki, 2023).
I found that mEC silencing reduced SPW-R occurrence, altered their spike content and suppressed their relationship with neocortical UP-DOWN states. These results suggest that a main role of mEC is to select neuronal assemblies of SPW-Rs and temporally coordinate their occurrences with neocortical events (Zutshi & Buzsáki, 2023).
Data from a 64-site recording session along the CA1-DG axis as the mouse is in its home cage. Top , spike rasters from CA1 interneurons (dark purple), CA3/DG interneurons (light purple), CA1 pyramidal cells (dark yellow) and CA3/DG pyramidal cells (light yellow). Bottom , Current source density , calculated from the LFP. mEC optogenetic silencing is marked by a solid blue line, and a “Stim ON” label. Notice a huge reduction in sharp wave ripples upon mEC silencing.