What is the role of astroglial calcium signaling in hippocampal memory encoding?

How do you remember what you did yesterday or even twenty years ago? A landmark discovery in memory research revealed that neural activity patterns of daily life experiences repeat themselves when we are asleep. Such reactivations, or replay, are important for long-term memory and is a well-accepted feature of the so-called place cells, i.e. nerve cells that fire at specific locations in space. While the link between place-cells, replay and memory function is an area of intense research, the role of astrocytes - a cell type in the brain originally proposed to play mostly supportive roles to nerve cells - is not explored. We aim to identify the roles of astrocytes in memory function during sleep.

How do you remember what you did yesterday or even twenty years ago? A landmark discovery in memory research revealed that neural activity patterns of daily life experiences repeat themselves when we are asleep. Such reactivation leads to memory consolidation by a cascade of synaptic plasticity mechanisms. This replay is a well-accepted feature of the so-called place cells, i.e. hippocampal neurons that fire at specific locations in space. While the link between place-cells, replay and memory consolidation is an area of intense research, the role of other cell types in the circuit, however, remains unexplored. Specifically, the role of astrocytes - a cell type that has been shown to play an important role in synaptic plasticity - has not been investigated in the context of neural replay because the tools to test these functions have been lacking until recently. Here, I hypothesize that astroglial calcium signals modulate hippocampal replay. By using two-photon microscopy, electrophysiology, optogenetics and pharmacogenetics, I aim to identify the role of astroglial calcium signaling in memory consolidation during sleep. I have the technical expertise, background in hippocampal circuits, and I have strong national and international collaborators that are essential for realizing this cutting-edge project. Finally, I will present important preliminary data obtained towards this proposal that demonstrate the feasibility of the methods.