Alpha connectivity and inhibitory control in adults with autism spectrum disorder

Veronica Yuk,Benjamin T Dunkley,Evdokia Anagnostou,Margot J Taylor

doi:10.1186/s13229-020-00400-y

Abstract

BackgroundIndividuals with autism spectrum disorder (ASD) often report difficulties with inhibition in everyday life. During inhibition tasks, adults with ASD show reduced activation of and connectivity between brain areas implicated in inhibition, suggesting impairments in inhibitory control at the neural level. Our study further investigated these differences by using magnetoencephalography (MEG) to examine the frequency band(s) in which functional connectivity underlying response inhibition occurs, as brain functions are frequency specific, and whether connectivity in certain frequency bands differs between adults with and without ASD.MethodsWe analysed MEG data from 40 adults with ASD (27 males; 26.94 ± 6.08 years old) and 39 control adults (27 males; 27.29 ± 5.94 years old) who performed a Go/No-go task. The task involved two blocks with different proportions of No-go trials: Inhibition (25% No-go) and Vigilance (75% No-go). We compared whole-brain connectivity in the two groups during correct No-go trials in the Inhibition vs. Vigilance blocks between 0 and 400 ms.ResultsDespite comparable performance on the Go/No-go task, adults with ASD showed reduced connectivity compared to controls in the alpha band (8–14 Hz) in a network with a main hub in the right inferior frontal gyrus. Decreased connectivity in this network predicted more self-reported difficulties on a measure of inhibition in everyday life.LimitationsMeasures of everyday inhibitory control were not available for all participants, so this relationship between reduced network connectivity and inhibitory control abilities may not be necessarily representative of all adults with ASD or the larger ASD population. Further research with independent samples of adults with ASD, including those with a wider range of cognitive abilities, would be valuable.ConclusionsOur findings demonstrate reduced functional brain connectivity during response inhibition in adults with ASD. As alpha-band synchrony has been linked to top-down control mechanisms, we propose that the lack of alpha synchrony observed in our ASD group may reflect difficulties in suppressing task-irrelevant information, interfering with inhibition in real-life situations.

Highlights

Individuals with autism spectrum disorder (ASD) often report difficulties with inhibition in everyday life
As alpha-band synchrony has been linked to top-down control mechanisms, we propose that the lack of alpha synchrony observed in our ASD group may reflect difficulties in suppressing task-irrelevant information, interfering with inhibition in real-life situations
As considerable evidence has suggested that ASD may be characterized by patterns of altered functional connectivity [61, 75,76,77,78,79], we focused our analyses of inhibitory control in ASD on this aspect of neural function

Summary

Introduction

Individuals with autism spectrum disorder (ASD) often report difficulties with inhibition in everyday life. Electroencephalographic (EEG) studies have revealed that peaks in event-related potentials at around 200 and 300 ms are associated with conflict monitoring and motor inhibition, respectively [26,27,28,29] This neural activity consists of oscillations at different frequencies, in the theta (4–7 Hz), alpha (8–14 Hz), beta (15–30 Hz), and gamma (> 30 Hz) bands, each of which plays a certain role in successful inhibition. Modulation of gamma activity may reflect changes in the balance of local excitatory and inhibitory neural activity that underlies a variety of cognitive functions, including response inhibition and other executive functions [42,43,44,45,46,47] How these brain regions convey information through long-range synchrony to exert inhibitory control has not been well investigated. It is important to better understand how connectivity facilitates inhibition, especially in the context of ASD, as people with ASD have demonstrated reduced long-range connectivity patterns in a wide range of domains, especially in the lower frequency bands [57,58,59,60] (see [61] for a review)

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