Disrupted integration of exteroceptive and interoceptive signaling in autism spectrum disorder

Abstract

In addition to deficits in social communication, individuals diagnosed with Autism Spectrum Disorder (ASD) frequently exhibit changes in sensory and multisensory function. Recent evidence has focused on changes in audiovisual temporal processing, and has sought to relate these sensory-based changes to weaknesses in social communication. These changes in audiovisual temporal function manifest as differences in the temporal epoch or "window" within which paired auditory and visual stimuli are integrated or bound, with those with ASD exhibiting expanded audiovisual temporal binding windows (TBWs). However, it is unknown whether this impairment is unique to audiovisual pairings, perhaps because of their relevance for speech processing, or whether it generalizes across pairings in different sensory modalities. In addition to the exteroceptive senses, there has been growing interest in ASD research in interoception (e.g., the monitoring of respiration, heartbeat, hunger, etc.), as these internally directed sensory processes appear to be altered as well in autism. In the current study, we sought to examine both exteroception and interoception in individuals with ASD and a group of typically developing (TD) matched controls, with an emphasis on temporal perception of audiovisual (exteroceptive) and cardiovisual (interoceptive to exteroceptive) cues. Results replicate prior findings showing expanded audiovisual TBWs in ASD in comparison to TD. In addition, strikingly, cardiovisual TBWs were fourfold larger in ASD than in TD, suggesting a putative complete lack of cardiovisual temporal acuity in ASD individuals. Results are discussed in light of recent evidence indicating a reduced tendency to rely on sensory priors in ASD. Autism Res 2018, 11: 194-205. Lay Summary: Studies have shown that individuals with autism have difficulty in separating auditory and visual events in time. People with autism also weight sensory evidence originating from the external world and from their body differently. We measured simultaneity judgments regarding visual and auditory events and between visual and heartbeat events. Results suggest that while individuals with autism show unusual temporal function across the senses in a general manner, this deficit is greater when pairings bridged between the external world and the internal body.

Audiovisual temporal integration and rapid temporal recalibration in adolescents and adults: Age‐related changes and its correlation with autistic traits

“…Finally, we found a lack of significant correlation between multisensory temporal acuity and autistic and schizotypal traits. Our result is in fact consistent with two previous studies investigating autistic symptoms in nonclinical populations, both of which did not find any significant correlation between autistic traits and the size of the audiovisual TBW [Donohue et al, 2012;Noel, Lytle, et al, 2018], although individuals with higher levels of autistic traits showed a PSS shift to perceive auditoryleading stimuli as simultaneous [Donohue et al, 2012]. Our finding therefore further reduces the possibility that enlarged TBW may reflect a shared characteristic in clinical and subclinical populations.…”

“…In function (1), the mean of the best-fitting distribution was taken as a measure of PSS and the standard deviation was taken as the TBW [Noel, Lytle, Cascio, & Wallace, 2018;Noel, Stevenson, & Wallace, 2018]. The amplitude was free to vary and could exceed 1.…”

Links between self-injury and suicidality in autism

“…Interoception is closely related to (or indeed an aspect of) alexithymia [114,115], a feature of both eating disorders and autism. Interoceptive awareness of one's "visceral afferent information" [111] is also, of course, closely related to differences in the processing and integration of externally-generated or exteroceptive sensory experiences [116]. As such, the exteroceptive processing differences (and indeed alexithymia) observed in our self-harming sample [40] might have been accompanied by interoceptive differences which could contribute to self-injurious behaviors.…”

From multisensory integration in peripersonal space to bodily self‐consciousness: from statistical regularities to statistical inference

“…In turn, the priors reflect accumulated history of sensory likelihoods, and hence if low‐level sensory processing is altered, over the course of many exposures, priors—cognition—will be distorted as well. Fittingly, multisensory integration is well documented to be anomalous in autism spectrum disorder and schizophrenia (SZ), among other psychopathologies, and these—in particular SZ—are considered to be disorders of the self . Furthermore, much of the recent evidence suggesting deficitary sensory processing in psychopathology is highlighting the presence of either weak or inflexible priors .…”