Cortical networks in asleep and awake animals exhibit a diversity of dynamical states, ranging from synchronous to asynchronous patterns of activation. During periods of synchronous activity (“slow oscillations”) neurons tend to fire in a high correlated fashion fluctuating between periods of high synaptic activity (Up-state) and periods of relative silence (Down state). On the other hand, the asynchronous state is characterized by low mean spiking correlations possibly resulting from excitatory and inhibitory inputs cancelling each other.
We are interested in understanding how different cortical dynamics can be present in the same network and we hypothesize that serotonin might play a role in this transition.
We performed electrophysiological recordings both in vitro and in vivo in entorhinal cortex of the mouse brain while inducing the release of serotonin (5-HT) pharmacologically (using MDMA or Fenfluramine) and we observed a modulation of ongoing slow oscillations simultaneously with the activation of a subgroup of inhibitory interneurons. The 5-HT2A receptor seems to be necessary for the interneurons activation mediated by serotonin