Development and organization of memory circuits

The hippocampus spontaneously generates sequences of assembly activation that mirror its function in organizing experience in time and space. These sequences arise from the interaction between external sensory inputs and internally-generated self-organized activity.During development, spontaneous hippocampal dynamics are tightly correlated to sensorimotor inputs and highly coordinated among most neurons through the action of early born GABA hub cells (Bonifazi et al. 2009, Picardo et al. 2012, Bocchio et al. 2020, Bollmann et al. 2023). In contrast, internal dynamics are a strong organizing factor in the adult hippocampus and spontaneous activity is dominated by a sparse, but stable subset of active neurons organized in functionally orthogonal “assemblies” (Malvache et al. 2016).
In sum, there is both an internalization and a sparsification of hippocampal dynamics as development proceeds with the emergence of basic functional modules in the form of hippocampal assemblies. Both processes are likely to rely on the development of functional GABAergic circuits (Dard et al. 2021, Leprince et al. 2022).

Our lab studies the circuit basis of hippocampal assemblies from development into adulthood and across different states of the normal and pathological brain. In particular, we want to understand how development shapes the final wiring diagram of adult hippocampal assemblies. We also study the barrel cortex, as a model of sensory-driven brain area.

To describe the circuit basis of cortical dynamics, we have developed a unique multidisciplinary approach that combines ex vivo and in vivo calcium imaging, electrophysiology, holographic photo-stimulation, neuroanatomy, data mining, mouse genetics and behavior.