Autism Sensory Profiles Predict Stimulus- Evoked Insula Connectivity

Area of Science:

• Neuroscience
• Psychiatry
• Genetics

Background:

• Sensory processing differences are common in autism spectrum disorder (ASD).
• Existing research often attempts to categorize these differences into subtypes, but this approach may not fully capture the complexity of sensory experiences.
• The underlying neurobiological basis of sensory heterogeneity in ASD remains unclear.

Purpose of the Study:

• To characterize the structure of sensory processing differences in ASD using continuous models.
• To investigate the neurobiological relevance of this characterization using functional connectivity.
• To explore potential sex differences in the relationship between sensory profiles and neurobiology.

Main Methods:

• Applied unsupervised spectral manifold dimensionality reduction to item-level Sensory Profile data from 223 autistic participants.
• Utilized voxel-wise linear mixed-effects modeling of insula-seeded functional connectivity in 63 participants.
• Analyzed data during externally driven stimulation (motion stimuli) and resting state.

Main Results:

• Categorical subtyping of sensory profiles in ASD proved unstable and irreproducible.
• Sensory processing differences are best modeled as a continuous, non-linear manifold of sensory severity.
• Higher sensory severity correlated with disrupted insula-sensorimotor connectivity during motion stimulation, but not at rest.
• A significant sex-by-sensory gradient interaction indicated males showed heightened sensitivity.

Conclusions:

• Sensory atypicality in ASD is better represented as a continuous regulatory manifold rather than discrete subtypes.
• Context-dependent hypoconnectivity, particularly during sensory stimulation, is linked to sensory severity in ASD.
• Findings suggest disrupted social-sensory integration underlies sensory differences in ASD, with males exhibiting greater vulnerability.