High internal noise and poor external noise filtering characterize perception in autism spectrum disorder

Loisa Bennetto,Kimberly B Schauder,Woon Ju Park,Duje Tadin,Ruyuan Zhang

doi:10.1038/s41598-017-17676-5

Loisa Bennetto, Kimberly B Schauder + Show 3 more

Open Access

https://doi.org/10.1038/s41598-017-17676-5

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Abstract

An emerging hypothesis postulates that internal noise is a key factor influencing perceptual abilities in autism spectrum disorder (ASD). Given fundamental and inescapable effects of noise on nearly all aspects of neural processing, this could be a critical abnormality with broad implications for perception, behavior, and cognition. However, this proposal has been challenged by both theoretical and empirical studies. A crucial question is whether and how internal noise limits perception in ASD, independently from other sources of perceptual inefficiency, such as the ability to filter out external noise. Here, we separately estimated internal noise and external noise filtering in ASD. In children and adolescents with and without ASD, we computationally modeled individuals’ visual orientation discrimination in the presence of varying levels of external noise. The results revealed increased internal noise and worse external noise filtering in individuals with ASD. For both factors, we also observed high inter-individual variability in ASD, with only the internal noise estimates significantly correlating with severity of ASD symptoms. We provide evidence for reduced perceptual efficiency in ASD that is due to both increased internal noise and worse external noise filtering, while highlighting internal noise as a possible contributing factor to variability in ASD symptoms.

Highlights

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and the presence of restricted and repetitive behaviors[1]
We found evidence for elevated internal noise and poor external noise filtering in autism spectrum disorder (ASD)
The estimated internal noise was correlated with ASD symptom severity, suggesting that individual variability in internal noise may be related to ASD symptomatology

Summary

Introduction

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and the presence of restricted and repetitive behaviors[1]. In vision, fluctuations in the number of photons emitted by a light source can fundamentally limit our ability to detect dim light[3] Even when such fluctuations in external input are effectively held constant, perception and associated behavioral responses still exhibit significant variability[8,9]. At the core of this controversy lies the issue of whether a domain-general account of ASD, such as the ones involving elevated internal noise and neural variability, can truly explain the complex phenotypes in individual with ASD24 This has been further complicated by the fact that the estimates of neural variability have been based on responses to task-irrelevant stimuli[17,18,19,24,25], making it difficult to estimate the degree to which internal noise limits perceptual performance in ASD

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