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The Go/No-Go Task Online: Evidence of an Inhibitory/Excitatory Imbalance in Autism in a Large Sample

Thursday, May 14, 2015: 11:30 AM-1:30 PM
Imperial Ballroom (Grand America Hotel)
F. Uzefovsky1, C. Allison2, P. Smith3 and S. Baron-Cohen1, (1)Autism Research Centre, University of Cambridge, Cambridge, United Kingdom, (2)Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom, (3)Autism Research Centre, Cambridge University, Cambridge, United Kingdom
Background:  

One theory of the aetiology of autism spectrum conditions (ASC) implicates an inhibitory/excitatory (E/I) imbalance in the brain. This theory has been supported by neuroimaging findings, findings implicating GABA receptor genes, and the comorbidity of epilepsy. However, behavioural manifestations of this imbalance, i.e. motor inhibition, primarily measured as an increase in false alarm response during a Go/No-go (GNG) paradigm, have been mixed. Some studies report decreased inhibition in individuals diagnosed with ASC relative to controls, others find this effect under specific conditions only (e.g. higher working memory load, social GNG) and others still find no difference between ASC and controls.

Objectives:  

In the current study we aimed to better understand behavioural inhibition in ASC by examining GNG performance in a large sample of ASC and controls.

Methods:  

Participants were 213 high-functioning adults diagnosed with ASC (103 females) and 414 controls (285 females) who completed a GNG task. The GNG task consisted of 300 trials; 220 trials elicited a Go response (pressing an arrow key) and 80 trials (26.7%) elicited a No-go response (not pressing any key). A Go response in a No-go trial was counted as a false alarm (FA) response. The effect of diagnosis on FA was examined.

Results:

As predicted by the E/I theory, individuals diagnosed with ASC had a significantly higher rate of FA errors than controls (t(625)=-3.45, p<.001, Cohen’s d=-.28). 

Conclusions:  

Utilizing a large sample of high-functioning individuals diagnosed with ASC and controls we find a significant effect of diagnosis on number of FA errors. This finding should be explored as a behavioural phenotypic measure alongside neuroimaging studies of motor inhibition, measures of GABA-ergic activity, and in the context of polymorphisms in the GABA receptor genes, to better understand its potential role in the aetiology of autism.

See more of: Cognition: Attention, Learning, Memory
See more of: Cognition: Attention, Learning, Memory