Atypical sensory traits and changes in white matter microstructures connected to the amygdala and hippocampus of the autistic brain.
Autism spectrum disorder (ASD) is characterized by atypical sensory traits. The amygdala and hippocampus have been implicated in ASD, but how sensory traits relate to white matter pathways connected to these regions remains unclear. We therefore examined whether sensory traits are associated with microstructural properties of amygdala- and hippocampus-connected white matter in adults with ASD. We included 40 adults with ASD and 83 typically developing (TD) adults (all aged ≥ 18 years). Participants completed the Adolescent/Adult Sensory Profile (AASP) and underwent diffusion tensor imaging. Diffusion metrics were computed for bilateral amygdala-connected white matter (AWM) and hippocampus-connected white matter (HWM). The ASD group showed lower fractional anisotropy (FA) in both AWM and HWM than the TD group. In the ASD group, sensation-seeking scores revealed a nominal positive association with FA in the right AWM, although this association did not survive FDR correction. In the TD group, sensation-seeking scores were negatively associated with FA in the right HWM. Fisher r-to-z tests with FDR correction indicated significant group differences in the associations between sensation seeking and FA of the right AWM and right HWM. White matter microstructure in pathways connected to the amygdala and hippocampus showed group differences in FA and in how FA related to sensation seeking. These findings suggest that atypical sensory traits in ASD may be linked to microstructural differences in amygdala- and hippocampus-connected pathways.