Microglial morphodynamics and synaptic homeostasis

Microglia, the resident immune cells of the brain, have been extensively studied in the context of development and pathological conditions. It is well-established that they invade the central nervous system (CNS) early in development, becoming the brain's resident immune cells. While their immune functions are well-characterized, much less is known about their role in the healthy adult CNS. One of the most striking features of microglia in the non-pathological adult brain is their highly dynamic, ramified processes, which constantly survey the brain's parenchyma. Although this motility was initially thought to serve as a surveillance mechanism for detecting damage-associated molecular patterns or pathogens, recent evidence suggests that microglial processes frequently interact with neuronal cell bodies and synapses, hinting at a potential role in neuronal homeostasis.

Given that sleep is a crucial state for neuronal activity modulation, including processes like synaptic scaling, we have begun to explore the mechanisms governing microglial morphodynamics and their interactions with neurons during wakefulness and sleep. Using a combination of electrophysiology and in vivo imaging, our findings reveal that the control of microglial morphodynamics is intricately linked to neuronal activity and involves direct signaling between neurons and microglia. This regulation, which is not yet fully understood, may have significant implications for our understanding of sleep-dependent memory processes and brain homeostasis.

Keywords: Microglia, Morphodynamics, Sleep, Neuronal activity, Brain homeostasis.

Olivier Pascual est invité par Homaira Nawabi et Stéphane Belin.