Arousal State Influence On Neocortical Spontaneous and Visually-Evoked Activity Across Postnatal Development

Manal Salmi
Postdoctoral Research Fellow | Batista-Brito Lab
Albert Einstein College of Medicine – New York

Résumé : Sensory perception allows us to receive and integrate information from environment—a process that begins at birth. Remarkably, newborns can engage in sensorimotor behaviors without prior exposure to patterned sensory input. In mice, the first two postnatal weeks represent a critical period for cortical circuit assembly, during which spontaneous peripheral activity shapes the
development of functional networks and prepares the brain for active sensory processing. Thisdevelopmental window corresponds to the last trimester of human gestation, a highly sensitive
period for neurodevelopmental disorders.
In the primary visual cortex (V1), early development is marked by a transition from highly synchronized, self-generated activity driven by peripheral organs—such as retinal waves from
retina—to more decorrelated patterns capable of encoding external visual stimuli. In adults, arousal state is a critical factor regulating both spontaneous and sensory-evoked activity in V1.
However, how this modulation by arousal emerges during development remains poorly understood.
To address this, we recorded spontaneous and visually evoked population activity in V1 from postnatal day 9 (P9) to P18, spanning the period before and after eye opening (P13). We
combined dense extracellular electrophysiology with two-photon calcium imaging in awake, head-fixed pup mice, while simultaneously monitoring facial motion as a proxy for arousal state,
alongside visual stimulus presentation.
Before eye opening, cortical activity was largely unaffected by arousal. However, at eye opening onset, both spontaneous and visually evoked activity became significantly enhanced during higharousal states, mirroring adult-like modulation. This developmental turning point coincides with the shift from spontaneous, peripheral self-driven to sensory and internally driven cortical
activity and marks the emergence of arousal-dependent sensory processing in V1.
Understanding how spontaneous activity, external input, and arousal interact to shape cortical networks provides critical insight into normal brain development and may help uncover
mechanisms underlying neuropsychiatric conditions such as epilepsy, autism spectrum disorder, and schizophrenia.

Manal Salmi1 , Ehsan Sabri1 , Renata Batista-Brito1, 1 Albert Einstein College of Medicine, Dominick P. Purpura Department of Neuroscience, NYC, USA.
Email : manal.salmi@einsteinmed.edu , ehsan.sabri@gmail.com, renata.brito@einsteinmed.edu

Invitée par Stéphane Bugeon

Mardi 29 avril 2025 à 11h – Salle de conférence de l’Inmed