Insular functional connectivity in autistic and non-autistic development

There is evidence for altered interoceptive processing in individuals diagnosed with autism, compared to non-autistic individuals. At a neural level, functional and structural connectivity of interoceptive cortices may differ in autism, though developmental patterns of these differences are unclear as well as how these patterns may vary by subregion within the insular cortex. To better understand the roles of autism, age, and subregion in interoceptive connectivity patterns, we used a cross-sectional approach to examine interoceptive functional connectivity across individuals spanning a wide age range.

N = 59 autistic individuals (ages 7-54) and N = 71 non-autistic individuals (ages 7-51) completed a resting-state functional magnetic resonance imaging scan. From these scans, we analyzed seed-based functional connectivity of insula subregions (posterior, middle, and anterior) by hemisphere. We analyzed associations with age, group, and interoceptive self-reported experiences, as measured in a subset of individuals who completed the Body Perception Questionnaire.

We found that with age, primary interoceptive cortex showed decreased functional coupling with subcortical regions such as the thalamus and increased coupling with multimodal parietal regions. Functional connectivity within key interoceptive areas was decreased in those with increased reported body awareness. Differences between the autistic and non-autistic groups were minimal, with a single finding of heightened connectivity in autism between left posterior insula and lateral occipital cortex.

These findings shed light on potential developmental shifts in how interoceptive processing is balanced between lower-order and higher-order areas. Further, they provide background for how autistic patterns of interoceptive processing may be considered relative to age.