Transient and steady-state auditory gamma-band responses in first-degree relatives of people with autism spectrum disorder

Abstract

BackgroundStimulus-related γ-band oscillations, which may be related to perceptual binding, are reduced in people with autism spectrum disorders (ASD). The purpose of this study was to examine auditory transient and steady-state γ-band findings in first-degree relatives of people with ASD to assess the potential familiality of these findings in ASD.MethodsMagnetoencephalography (MEG) recordings in 21 parents who had a child with an autism spectrum disorder (pASD) and 20 healthy adult control subjects (HC) were obtained. Gamma-band phase locking factor (PLF), and evoked and induced power to 32, 40 and 48 Hz amplitude-modulated sounds were measured for transient and steady-state responses. Participants were also tested on a number of behavioral and cognitive assessments related to the broad autism phenotype (BAP).ResultsReliable group differences were seen primarily for steady-state responses. In the left hemisphere, pASD subjects exhibited lower phase-locked steady-state power in all three conditions. Total γ-band power, including the non-phase-locked component, was also reduced in the pASD group. In addition, pASD subjects had significantly lower PLF than the HC group. Correlations were seen between MEG measures and BAP measures.ConclusionsThe reduction in steady-state γ-band responses in the pASD group is consistent with previous results for children with ASD. Steady-state responses may be more sensitive than transient responses to phase-locking errors in ASD. Together with the lower PLF and phase-locked power in first-degree relatives, correlations between γ-band measures and behavioral measures relevant to the BAP highlight the potential of γ-band deficits as a potential new autism endophenotype.

Brain oscillations and connectivity in autism spectrum disorders (ASD): new approaches to methodology, measurement and modelling

“…Across visual and auditory paradigms the variations in GBA power effects (hypo-or hyperactivity) in ASD can be reconciled with the more consistent reports of reduced phaselocking in ASD and ASD-related populations where this was also assessed, noting that reduced phase-locking will be associated with an imbalance between evoked and induced power (Rojas et al, 2011 Delay in M100 evoked response; reduced gamma-band evoked activity at both time points Table 2: A summary of key electrophysiological studies into auditory processing in ASD.…”

Autistic Traits Below the Clinical Threshold: Re-examining the Broader Autism Phenotype in the 21st Century

“…Rojas et al (2011) took MEG recordings of 21 parents of autistic probands and 21 adult controls reporting a reduction in steady-state gamma-band responses in the autism-parent group, similar to the responses of children diagnosed with autism (e.g. Wilson et al 2007).…”

“…DTI, ERP and MEG studies of autistic probands and their relatives are also starting to provide further useful ways of exploring the neurodevelopmental pathways leading to autism by better understanding its biological liability (e.g. Elsabbagh et al 2009a;Rojas et al 2011).…”

Impaired Gamma-Band Activity during Perceptual Organization in Adults with Autism Spectrum Disorders: Evidence for Dysfunctional Network Activity in Frontal-Posterior Cortices

“…In the auditory domain, reduced entrainment to auditory stimulation at 40 Hz in participants with ASD (Wilson et al, 2007) as well as their firstdegree relatives (Rojas et al, 2011) has been demonstrated. In contrast, during visual perception there is evidence for both hyperactivity and hypoactivity of gamma-band oscillations (Grice et al, 2001;Brown et al, 2005;Milne et al, 2009;Isler et al, 2010;Stroganova et al, 2012), raising the question of the link between high-frequency oscillations and perceptual dysfunctions in the disorder.…”