Shared and divergent alteration of whole-brain connectivity and sensory deficits in multiple autism mouse models

Autism spectrum disorder (ASD) is a heterogeneous developmental disconnection syndrome. Identifying circuit deficits is crucial for understanding ASD etiology, yet the involvement of multiple brain regions and genetic variations complicates this analysis. Here, using an AI-powered mapping platform, BM-auto (Brain Mapping with Auto-ROI correction), to analyze a Thy1-YFP reporter, we show that different ASD-associated mutations cause distinct circuit abnormalities but share common deficits in the piriform cortex, a region regulating olfactory discrimination and social behavior patterns. We analyzed the whole-brain distribution of the Thy1-YFP reporter in three ASD mouse models (Tbr1^+/-, Nf1^+/-, and Vcp^+/R95G). YFP signals revealed altered axonal projections and structural connectivity. We also found that Thy1-YFP⁺ cell numbers varied across brain regions, revealing deficits in the differentiation or maintenance of projection neurons. While each mutation caused unique connectivity alterations, sensory regions-including the visual, somatosensory, and piriform cortices-were recurrently affected. However, effects on the visual and somatosensory cortices varied between models. The piriform cortex was the only region consistently impaired, showing reduced YFP signals and fewer Thy1-YFP⁺ neurons across all three models. Furthermore, all three mutants exhibited common olfactory discrimination impairments. Manipulating piriform cortex activity altered social behavior patterns, highlighting its role in ASD-linked circuit dysfunction. These findings underscore the vulnerability of sensory regions-especially the piriform cortex-to ASD-related mutations, strengthening the notion that altered sensory experiences are common in ASD.