Superior orientation discrimination and increased peak gamma frequency in autism spectrum conditions.

Dickinson, Abigail; Bruyns‐Haylett, Michael; Smith, Richard; Jones, Myles; Milne, Elizabeth

doi:10.1037/abn0000148

Cited by 30 publications

(64 citation statements)

References 83 publications

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“…In this study, slower binocular rivalry indicated disruption to E/I balance in ASD, although no group differences were found in occipital GABA levels. Dickinson et al (2016) found a significant difference between orientation discrimination thresholds and peak gamma frequency in ASD, concluding that both variables pointed towards increased inhibition in ASD. Future studies could be much more ambitious in this regard, and it is hoped that future researchers will be able to obtain data from multiple methodologies from the same individual in order to more clearly identify the way in which E/I balance is altered in ASD (if at all).…”

Section: Resultsmentioning

confidence: 80%

“…We have recently found that orientation discrimination thresholds are decreased in adults with ASD (Dickinson et al, 2016, although see Schwarzkopf, Anderson, de Haas, White, & Rees, 2014Shafai, Armstrong, Iarocci, & Oruc, 2015), and also that orientation discrimination thresholds correlate with autistic traits in the neurotypical population (Dickinson, Jones, & Milne, 2014). Inhibitory mechanisms are implicated in orientation discrimination as they are known to be involved in tuning the orientation selectivity of cells, as orientation selective neurons become narrowly tuned to a particular orientation through lateral inhibition (Hubel & Wiesel, 1968), and GABAergic inhibition has been shown to directly influence orientation discrimination ability.…”

Section: Perceptual Discriminationmentioning

confidence: 98%

“…Some studies have shown that visuallyinduced peak gamma frequency is correlated with resting GABA levels in occipital cortex Gaetz, Edgar, Wang, & Roberts, 2011;Muthukumaraswamy et al, 2009) although others have failed to replicate this relationship (Cousijn et al, 2014;Saxena et al, 2013). The technical difficulty in measuring GABA concentration in vivo with MRS and the different scan parameters used in these studies may contribute to the lack of convergence in results, Nevertheless, peak gamma frequency elicited by visual stimuli has been found to be higher in ASD (Dickinson et al, 2016), and correlated with autistic traits in the neurotypical population (Dickinson, Bruyns-Haylett, Jones, & Milne, 2015). In light of previous literature Muthukumaraswamy et al, 2009) this suggests that inhibition is increased in participants with ASD.…”

Section: High Frequency Neural Oscillations (Gamma-band Activity)mentioning

confidence: 99%

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Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

2016

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The balance of neural excitation and inhibition (E/I balance) is often hypothesised to be altered in autism spectrum disorder (ASD). One widely held view is that excitation levels are elevated relative to inhibition in ASD. Understanding whether, and how, E/I balance may be altered in ASD is important given the recent interest in trialling pharmacological interventions for ASD which target inhibitory neurotransmitter function.Here we provide a critical review of evidence for E/I balance in ASD. We conclude that data from a number of domains provides support for alteration in excitation and inhibitory neurotransmission in ASD, but when considered collectively, the available literature provide little evidence to support claims for either a net increase in excitation or a net increase in inhibition. Strengths and limitations of available techniques are considered, and directions for future research discussed.3

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Section: Resultsmentioning

confidence: 80%

Section: Perceptual Discriminationmentioning

confidence: 98%

Section: High Frequency Neural Oscillations (Gamma-band Activity)mentioning

confidence: 99%

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Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

2016

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“…Previous work has found superior orientation discrimination in individuals with ASD (Dickinson et al 2016). In contrast to the current work, this study employed an adaptive staircase which converged on 79% correct to measure perceptual thresholds (Dickinson et al 2016).…”

Section: Discussionmentioning

confidence: 93%

“…Some of the participants (17 with ASD and 9 NT controls) had taken part in our previous study measuring orientation discrimination (Dickinson et al, 2016).…”

Section: Methods Participantsmentioning

confidence: 99%

Understanding perceptual judgment in autism spectrum disorder using the drift diffusion model.

Pirrone¹,

Dickinson²,

Gomez³

et al. 2017

Neuropsychology

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Objective: Two-alternative forced-choice tasks are widely used to gain insight into specific areas of enhancement or impairment in individuals with autism spectrum disorder (ASD).Data arising from these tasks have been used to support myriad theories regarding the integrity, or otherwise, of particular brain areas or cognitive processes in ASD. The drift diffusion model (DDM) provides an account of the underlying processes which give rise to accuracy and reaction time distributions, and parameterises these processes in terms which have direct psychological interpretation. Importantly, the DDM provides further insight into the origin of potential group differences in task performance. Here, for the first time, we used the DDM to investigate perceptual decision making in ASD.Method: Adults with (N = 25) and without ASD (N = 32) performed an orientation discrimination task. A drift diffusion model was applied to the full RT distributions. Results:Participants with ASD responded more slowly than controls, the groups did not differ in accuracy. Modelled parameters indicated that: (i) participants with ASD were more cautious than controls (wider boundary separation); (ii) non-decision time was increased in ASD; and (iii) the quality of evidence extracted from the stimulus (drift rate) did not vary between groups.Conclusions: Taking the behavioural data in isolation would suggest reduced perceptual sensitivity in ASD. However, DDM results indicated that despite response slowing, there was no evidence of differential perceptual sensitivity between participants with and without ASD.Future use of the DDM in investigations of perception and cognition in ASD is highly recommended.

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A Magnetic Resonance Spectroscopy Study of Superior Visual Search Abilities in Children with Autism Spectrum Disorder

et al. 2020

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Although diagnosed on the basis of deficits in social communication and interaction, autism spectrum disorder (ASD) is also characterized by superior performance on a variety of visuospatial tasks, including visual search. In neurotypical individuals, region‐specific concentrations of the inhibitory neurotransmitter gamma‐aminobutyric acid (GABA) are associated with individual differences in attention and perception. While it has been hypothesized that ASD may be associated with an excitatory–inhibitory imbalance, it remains unclear how this may contribute to accelerated visual search performance in individuals with ASD. To investigate this, 21 children with ASD and 20 typically developing children participated in a visual search task and a magnetic resonance spectroscopy study to detect neurochemical concentrations, including GABA. Region‐specific neurochemicals were examined in the right frontal eye fields, right temporal–parietal junction (rTPJ), and bilateral visual cortex (VIS). GABA concentrations did not differ between groups; however, in children with ASD, greater GABA concentration in the VIS was related to more efficient search. Additionally, lower VIS GABA levels were also associated with increased social impairment. Finally, we found reduced N‐acetyl aspartate, total creatine, glutamate and glutamine (Glx), GABA/Glx in the rTPJ, suggestive of neuronal dysfunction in a critical network hub. Our results show that GABA concentrations in the VIS are related to efficient search in ASD, thus providing further evidence of enhanced discrimination in ASD. Autism Res 2020, 13: 550–562. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary Children with autism spectrum disorder (ASD) often perform better than their non‐ASD peers on visual search tasks; however, it is unclear how they achieve this superior performance. Using magnetic resonance spectroscopy to measure neurochemicals in the brain, we found that the level of one, gamma‐aminobutyric acid, in the visual cortex was directly related to search abilities in children with ASD. These results suggest that faster search may relate to enhanced perceptual functioning in children with ASD.

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Superior orientation discrimination and increased peak gamma frequency in autism spectrum conditions.

Cited by 30 publications

References 83 publications

Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

Measuring neural excitation and inhibition in autism: Different approaches, different findings and different interpretations

Understanding perceptual judgment in autism spectrum disorder using the drift diffusion model.

A Magnetic Resonance Spectroscopy Study of Superior Visual Search Abilities in Children with Autism Spectrum Disorder

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