Bridging the Internal and External Sensory Worlds in Autism

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PROJECT SUMMARY Altered sensory experiences are prevalent in autism and have been implicated in not only the core behavioral characteristics of impaired social communication and repetitive behaviors, but in a range of associated comorbidities including sleep disturbances2 and anxiety24. Recent work in the sensory domain strongly suggests that the predictability, or lack thereof, of sensory stimuli heavily influences aberrant reactions and mediates relations between sensory sensitivity, anxiety, and social motivation in autism78-79. Most sensory research thus far has emphasized exteroceptive sensation—sensory signals that originate in the external environment—with less work on interoceptive sensation—sensory signals that arise from the viscera and skin to signal the brain about the physiological condition of the body6. These interoceptive cues are often the precursors of emotional experience, and thus have significant transdiagnostic clinical relevance in psychiatry. Evaluation of the emotional relevance of the external environment—within which social stimuli are embedded—requires a continuous exchange of information between exteroceptive and interoceptive processing streams. In other words, successful navigation of the social world depends on multisensory integration across the body boundary. Critically for autism, many visceral interoceptive signals tend to be very rhythmic (e.g., cardiac signals), and/or are under voluntary control (e.g., respiratory signals) and are thus far more predictable than environmental exteroceptive cues. This predictability is enhanced on average in individuals with autism, who tend to have higher heart rates and lower heart rate variability than controls. In the current project period, we found evidence for profoundly disrupted temporal integration of visceral interoceptive and exteroceptive signals, without clear evidence of disrupted interoception alone. We now propose, in this renewal, to isolate and test potential neural drivers and clinical sequelae of this disrupted integration. The proposed work will provide important new insights into the consequences of sensory processing deficits in autism that go beyond exteroceptive sensation, incorporating a sensory milieu that has high relevance for social-emotional functioning.