Unreliable Evoked Responses in Autism

Abstract

Summary Autism has been described as a disorder of general neural processing, but the particular processing characteristics that might be abnormal in autism have mostly remained obscure. Here, we present evidence of one such characteristic: poor evoked response reliability. We compared cortical response amplitude and reliability (consistency across trials) in visual, auditory, and somatosensory cortices of high-functioning individuals with autism and controls. Mean response amplitudes were statistically indistinguishable across groups, yet trial-by-trial response reliability was significantly weaker in autism, yielding smaller signal-to-noise ratios in all sensory systems. Response reliability differences were evident only in evoked cortical responses and not in ongoing resting-state activity. These findings reveal that abnormally unreliable cortical responses, even to elementary non-social sensory stimuli, may represent a fundamental physiological alteration of neural processing in autism. The results motivate a critical expansion of autism research to determine whether (and how) basic neural processing properties such as reliability, plasticity, and adaptation/habituation are altered in autism.

A computational perspective on autism

“…To the extent that a Bayesian prior accurately reflects the statistics of the world, it will improve task performance by reducing the number of probable stimuli. As such, an attenuated prior in autism could potentially increase behavioral sensitivity to sensory noise, as well as increase variability in stimulus-driven neural activity, both of which are consistent with recent findings on the disorder (47,48). We next simulate how Bayesian priors can be implemented through divisive normalization, establishing a link between alterations in neural computation and high-level hypotheses about how autism affects the ability to perform statistical inference.…”

“…Given the statistical properties of spiking neural activity (79), this result also predicts greater trial-by-trial response variability in autism. Evidence supporting these predictions comes from imaging studies reporting larger stimulus-driven response amplitudes (80) or increased variance (47) in autism, as well as recent psychophysical findings (81). In one imaging study, increased stimulus-driven activity in auditory cortex associated with lowlevel feature processing was observed in subjects with autism compared to typically developing controls (82).…”

Brain dynamics in ASD during movie‐watching show idiosyncratic functional integration and segregation

“…Interestingly, it has recently been suggested that increased visual responsiveness to low‐level features, as reported in this study, may arise due to a larger noise in the primary visual system (Simmons et al, 2009; Lawson, Rees, & Friston, 2014). Along those lines, a larger intra‐individual variability of the evoked visual response has been reported in ASD (Dinstein et al, 2012; Haigh, Heeger, Dinstein, Minshew, & Behrmann, 2015). …”

Autonomic and brain responses associated with empathy deficits in autism spectrum disorder

“…Autism spectrum disorder (ASD) is a family of neurodevelopmental disorders with a wide range of sensory and socio-emotional deficits (Chiu, et al, 2008; Dinstein, et al, 2012; Happe, et al, 2006). Empathy, the ability to vicariously share feelings of others, is an important social-emotional faculty (Gu, et al, 2010; Moriguchi, et al, 2007) and is compromised in individuals with ASD (Baron-Cohen and Wheelwright, 2004).…”