Increased Self-Grooming Gates Adult Visual Cortical Plasticity through a Ventral Pallidum-Visual Cortex Pathway.

Repetitive behaviors are prominent features of multiple neurodevelopmental and psychiatric disorders, which are frequently accompanied by abnormalities in visual processing. However, whether repetitive behavioral states themselves actively regulate visual system and through what neural mechanisms remain unclear. Using a water spray paradigm that selectively increased self-grooming in male mice, we showed ocular-dominance plasticity in adult primary visual cortex (V1) was markedly enhanced. Neurons in the ventral pallidum (VP) were activated in synchrony with self-grooming behavior. VP inhibition abolished both grooming and plasticity, whereas VP activation was sufficient to boost both. Viral tracing identified a direct, predominantly GABAergic VP→V1 projection whose activity controlled V1 E/I balance and grooming-induced plasticity. In a pharmacological model of compulsive grooming induced by repeated meta-chlorophenylpiperazine administration, grooming intensity positively correlated with visual plasticity in a VP-dependent manner. Together, these findings identified the VP-V1 pathway as a critical circuit through which a grooming-associated behavioral state modulated adult visual cortical plasticity, revealing a previously unrecognized link between behavioral state and sensory cortical function.