Contribution of the cortico-hippocampal neuro-glial network to memory processing during sleep

Learning of complex motor tasks modifies local network activity in the primary motor cortex (M1), is substantially rehearsed during subsequent sleep and is associated with an interregional (i.e., cortico-striato-hippocampal) reorganization of the memory trace. In addition to neurons, this process critically depends on astrocytic calcium signalling. However, the learning-dependent in vivo patterns of coordinated neuro-glial activity, involved in memory formation during subsequent wake and sleep, remain unclear. Using chronic in vivo imaging this project studies, in a brain-state specific manner, neuronal and astroglial calcium signalling in M1 and the CA1 area of the hippocampus before, during and immediately after the complex wheel learning task as well as during preceding and subsequent sleep. The framing hypothesis is that the different brain states, i.e., wakefulness, NonREM and REM sleep, are characterized by distinct activity patterns of the neuro‐glial network which are changed by prior motor learning. Specifically, we test how learning performance, underlying task-specific activity patterns and interregional local field potentials (LFPs) are influenced by acute post-training sleep and sleep deprivation, and how network activity is re-activated post-training in a similar but not identical task, requiring generalization as a form of gist abstraction. Taken together our data shall provide an unprecedented insight into the in vivo interactions between neurons and neuroglia underlying complex motor learning and its consolidation by sleep.