Gamma Activation in Young People with Autism Spectrum Disorders and Typically-Developing Controls When Viewing Emotions on Faces

Abstract

BackgroundBehavioural studies have highlighted irregularities in recognition of facial affect in children and young people with autism spectrum disorders (ASDs). Recent findings from studies utilising electroencephalography (EEG) and magnetoencephalography (MEG) have identified abnormal activation and irregular maintenance of gamma (>30 Hz) range oscillations when ASD individuals attempt basic visual and auditory tasks.Methodology/Principal FndingsThe pilot study reported here is the first study to use spatial filtering techniques in MEG to explore face processing in children with ASD. We set out to examine theoretical suggestions that gamma activation underlying face processing may be different in a group of children and young people with ASD (n = 13) compared to typically developing (TD) age, gender and IQ matched controls. Beamforming and virtual electrode techniques were used to assess spatially localised induced and evoked activity. While lower-band (3–30 Hz) responses to faces were similar between groups, the ASD gamma response in occipital areas was observed to be largely absent when viewing emotions on faces. Virtual electrode analysis indicated the presence of intact evoked responses but abnormal induced activity in ASD participants.Conclusions/SignificanceThese findings lend weight to previous suggestions that specific components of the early visual response to emotional faces is abnormal in ASD. Elucidation of the nature and specificity of these findings is worthy of further research.

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

“…Rojas, Maharajh, Teale & Rogers, 2008) whereas other studies have found no difference in evoked (Gandal et al 2010;Wright et al 2012) or induced gamma power (Gandal et al 2010). Here, we found no significant difference in either evoked or induced peak gamma power between the participants with and without ASC.…”

Enhancing Anger Perception With Transcranial Alternating Current Stimulation Induced Gamma Oscillations

“…Refs. [10,36]) and suggest that occipital gamma plays a key role in facial emotion processing. Experiment 2: the role of occipital gamma in anger and facial identity perception Experiment 1 showed that modulating occipital gamma with tACS resulted in an improvement in anger perception relative to tACS in the alpha band.…”

“…Studies exploring this question have indicated that gamma oscillations are one mechanism underlying this process [3,28,30]. For example, in groups with deficits in emotion perception, such as Autism Spectrum Disorders (ASD; [34]), gamma oscillations have been reported to be reduced when perceiving emotion from faces [10,36].…”

“…Refs. [10,36]) we predicted that modulating occipital gamma with tACS would enhance performance relative to occipital alpha stimulation. Since we had no a priori reason to assume that occipital alpha stimulation would differ from sham stimulation, this form of stimulation was chosen as an active control condition in order to examine the extent to which occipital gamma stimulation may influence performance in a frequency specific manner.…”

Structural coding versus free-energy predictive coding

“…Clarity about the role of gamma synchronization is particularly relevant to understand effects of impaired gamma synchronization, as found in neurodevelopmental disorders such as schizophrenia (Uhlhaas, Silverstein, & Phillips, 2005) and autism spectrum disorders (ASD) (Grice et al, 2001;Maxwell et al, 2015;Milne et al, 2009;Sun et al, 2012;Wright et al, 2012). For instance, within FE predictive coding, Clark (2013) suggested that impaired gamma synchronization leads to an imbalanced precision associated with prediction errors, that is, a higher precision at lower levels relative to that at higher levels (see also Kanai et al, 2015).…”