Sequential reinstatement of neocortical activity during slow oscillations depends on cells’ global activity

Adrien Peyrache (1) , Karim Benchenane , Mehdi Khamassi , Sidney I Wiener , Francesco P Battaglia

1 Montreal Neurological Institute, McGill University

During Slow Wave Sleep (SWS), cortical activity is dominated by endogenous processes modulated by slow oscillations (0.1–1 Hz): cell ensembles fl uctuate between states of sustained activity (UP states) and silent epochs (DOWN states). We investigate here the temporal structure of ensemble activity during UP states by means of multiple single unit recordings in the prefrontal cortex of naturally sleeping rats. As previously shown, the fi ring rate of each PFC cell peaks at a distinct time lag after the DOWN/UP transition in a consistent order. We show here that, conversely, the latency of the fi rst spike after the UP state onset depends primarily on the session-averaged fi ring rates of cells (which can be considered as an indirect measure of their intrinsic excitability). This latency can be explained by a simple homogeneous process (Poisson model) of cell fi ring, with sleep averaged fi ring rates employed as parameters. Thus, at DOWN/UP transitions, neurons are affected both by a slow process, possibly originating in the cortical network, modulating the time course of fi ring for each cell, and by a fast, relatively stereotyped reinstatement of activity, related mostly to global activity levels.

Mots clés: UP/DOWN states; cerebral cortex; sleep; replay; electrophysiology; ensemble recordings; spike sequence; synfi re chains

Domaines: Neurosciences

Adrien Peyrache, Karim Benchenane, Mehdi Khamassi, Sidney I Wiener, Francesco P Battaglia. Sequential reinstatement of neocortical activity during slow oscillations depends on cells’ global activity. Frontiers in Systems Neuroscience, 2010, 3, ⟨10.3389/neuro.06.018.2009⟩. ⟨hal-02364210⟩