Memory formation emerges from coordinated interactions across genetically defined neuronal and glial cell populations, yet how distinct cell types shape hippocampal network dynamics remains largely unknown. In our laboratory, we combine large-scale electrophysiology, optogenetics, imaging, and closed-loop circuit manipulations to investigate how distinct neural populations cooperate to support memory processing.

Here, I will first present recent work revealing inhibitory circuit mechanisms underlying the formation and stabilization of hippocampal neuronal assemblies. Using high-density silicon probes integrated with miniaturized LEDs, we generated synthetic neuronal assemblies in behaving mice and identified the circuit mechanisms that determine their long-term incorporation into physiological memory reactivation. Further analyses suggest that similar inhibitory mechanisms support naturally occurring assembly formation during learning.

A natural next question is how molecular and cellular signaling coordinates network activity after learning to promote the selective recruitment of neurons into memory traces. To address this, we combine simultaneous large-scale neuronal recordings with astrocyte calcium imaging to investigate how glial activity shapes hippocampal network dynamics during memory consolidation. Our results reveal that astrocytic calcium transients are unexpectedly negatively correlated with the reactivation of recently formed neuronal assemblies, and that this relationship is dynamically modulated by learning. Ongoing experiments using cell-type-specific optogenetic manipulation of astrocytes are beginning to uncover their causal contribution to hippocampal memory dynamics.

More information:

• https://researchmar.net/programesrecerca/neurociencies/es_lab_computacio_neural.html