Sensory and motor deficits represent core features of autism spectrum disorder (ASD) and contribute to significant functional impairment. In the current application, we hypothesize a relationship between alterations in sensation and action in ASD, highlighting the importance of sensorimotor loops in attempting to understand mechanisms of impairment. In particular, we predict - to our knowledge, for the first time - that a breakdown in the link between action and perception leads to a different perceptual quality of self-generated motor acts in ASD. We propose a battery of translational experimental paradigms to test this novel hypothesis. All mobile organisms are equipped with a mechanism that serves to attenuate the sensory consequences of self-generated action, allowing enhanced processing of external information. Specifically, corollary discharge (CD) signals are sent to sensory brain areas and represent a copy of movement signals sent to lower motor regions. CD signals allow organisms to predict the sensory consequences of an imminent movement, such that sensory brain regions can attenuate their response to self-initiated action. In the auditory domain, CD allows dampening of the sensory response to self-generated sounds (e.g., speech). In the oculomotor domain, CD allows the visual system to prepare for change in retinal input following an eye movement. We propose that ASD is characterized by disturbances in CD signaling, such that affected individuals experience increased response to their own actions, potentially resulting in hypo-responsiveness to external sensory stimuli and internal preoccupation. Critically, these putative consequences of CD deficits are well- replicated ASD features, but CD itself has never been tested in ASD. Our approach is to capitalize on elegant behavioral paradigms derived from animal neurophysiology, in combination with eye tracking and electrophysiology (EEG), to evaluate the integrity of CD signals in children and adolescents with ASD, as compared to well-matched typically developing controls. We hypothesize that disturbances in CD in ASD will be evidenced in: (1) reduced attenuation of auditory EEG responses to self-generated sounds; and (2) altered visual perception and movement planning following a saccadic eye movement, consistent with a failure to use CD to compensate for this movement. We will explore whether CD deficits relate to clinical features, including not only sensory and motor symptoms, but also higher order deficits in social and empathic functioning, which could reflect downstream effects of basic sensorimotor alterations. To our knowledge, this study is the first investigation of CD in ASD. Thus, this innovative, translationally- grounded project addresses a key gap in ASD research and knowledge, using cognitive neuroscience techniques to probe a specific, well-characterized brain mechanism that may underlie core ASD features. Our findings have the potential to link core ASD features to activity of single neurons, providing unique insight into potential neural mechanisms driving symptoms in ASD and potentially offering novel targets for intervention.
. This project addresses core symptoms in autism spectrum disorder (ASD) from the perspective that deficits in the link between perception and action can drive not only sensory and motor symptoms that are hallmark features of ASD, but also higher-order social deficits. The project uses paradigms translated from animal studies to test the integrity of corollary discharge signals, which allow organisms to attenuate the sensory consequences of self-generated action and attune more fully to external input. In testing a specific neural mechanism, this work will contribute to our understanding of the brain basis of ASD, in turn furthering our understanding of the etiology of ASD and pointing toward new intervention targets.
|Foss-Feig, Jennifer H; Stavropoulos, Katherine K M; McPartland, James C et al. (2018) Electrophysiological response during auditory gap detection: Biomarker for sensory and communication alterations in autism spectrum disorder? Dev Neuropsychol 43:109-122|
|Foss-Feig, Jennifer H; Schauder, Kimberly B; Key, Alexandra P et al. (2017) Audition-specific temporal processing deficits associated with language function in children with autism spectrum disorder. Autism Res 10:1845-1856|