Experimental and computational analysis of REM sleep distributed cortical activity in mice

Rapid eye movement (REM) sleep is a sleep state exhibiting low-amplitude, high-frequency cortical activity, similar to wakefulness. However, recent studies have shown that certain cortical areas exhibit slow activity close to that of slow-wave sleep. The objective of the thesis is to better characterize the temporal-spatial distribution of these slow and fast oscillations, and then to propose a computational model to make predictions on the mechanisms responsible for this complex distribution of cortical activity.We first analysed multisite recordings of local field potential and showed that, in somatomotor areas, slow REM activity exhibits several differences from that of slow-wave sleep. In contrast, this activity is not observed in the hippocampus and mPFC.Secondly, we propose a model of the entire mouse cortex in REM, by implementing a hypothesis of heterogeneous neuromodulation within the cortex. This model is composed of a network of mean fields, connected to each other following the connectome of the mouse using The Virtual mouse Brain simulator, and with different levels of adaptation, in accordance with our biological results.Under these conditions, the model reproduces the distribution of slow and fast oscillations in the somatomotor and other cortical areas. Thus, we propose that a dynamic distribution of cholinergic signalling may explain specific features of REM cortical activity with respect to slow-wave sleep and wakefulness.