Both the mirror and the affordance systems might be impaired in adults with high autistic traits. Evidence from EEG mu and beta rhythms

Abstract

The association of autism spectrum disorder (ASD) with an altered mirror neuron system is still controversial. At the same time, the processing of object affordances by persons with ASD is a neglected issue. In this electroencephalographic study, adults differing in their autism quotient (AQ) scores were selected. We found anomalous modulation of mu and beta rhythms in high‐AQ, compared to low‐AQ persons, while they watched a set of goal‐directed manual actions. This confirms that observing actions involving implicit intentions most clearly reveals the impairment of the mirror neurons system (MNS). The high‐AQ group also showed anomalous mu and beta modulation when they looked at pictures of manipulable objects, indicating a deficit in processing motor affordances. We conclude that high‐AQ adults have neural impairment of both the MNS and the affordance systems, which could underlie their relational problems with both people and objects. Autism Res 2019, 12: 1032–1042. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary Adults with autistic traits (high‐autism quotient [AQ] scores) and matched controls (low‐AQ) observed intentional hand actions, and pictures of manipulable and non‐manipulable objects. The high‐AQ group compared to the control group, showed anomalous modulation of the electroencephalographic motoric rhythms (mu and beta) while observing familiar goal‐directed actions, confirming an impairment of their mirror neuron system. Also, their brain rhythms were anomalous when they watched manipulable objects, which suggest a dysfunction in their relation with objects (affordance system).

Autism-spectrum traits in neurotypicals predict the embodiment of manipulation knowledge about object concepts: Evidence from eyetracking

“…An imaging study of adults with ASD found that delays in the semantic processing of action words were tied to reduced activation of motor cortex, and also tied to symptom severity [ 49 ]. Adults high in autism-spectrum characteristics also showed atypical motor-related brain activity when viewing pictures of manipulable objects, perhaps reflecting deficits in processing motor affordances [ 50 ].…”

A Neural Model of Intrinsic and Extrinsic Hippocampal Theta Rhythms: Anatomy, Neurophysiology, and Function

“…iSTART proposes that various individuals with autism have their vigilance stuck at an abnormally high value due to abnormal cholinergic activity, leading to abnormal orienting and memory search, learning of hyperspecific recognition categories, and a narrow focus of attention. Abnormal iSTART orienting causes abnormal beta oscillations, which have been reported (Buard et al, 2018;de Vega et al, 2019). The breakdown of a fluent response to changing environmental challenges by autistic individuals would be expected to alter their theta rhythms.…”

A review of literature on the link between action observation and action language: advancing a shared semantic theory

“…Some authors suggest that the activation of the mirror neuron system could directly intervene in the retrieval of the meaning of the word (Barsalou, 2008;Fischer & Zwaan, 2008;Rizzolatti & Craighero, 2004;Zwaan & Taylor, 2006), whereas others suggest that this effect is just an epiphenomenon that accompanies accessing the meaning (Bedny & Caramazza, 2011;Caramazza, Anzellotti, Strnad, & Lingnau, 2014;Mahon & Caramazza, 2008). One way to better understand these alternative hypotheses could be to more systematically study action verb understanding in populations presenting atypical functioning in the mirror neuron system, such as in patients with autism (Dapretto et al, 2006;Manuel de Vega et al, 2019;Martineau, Andersson, Barthelemy, Cottier, & Destrieux, 2010) or schizophrenia (Enticott et al, 2008;Mehta, Thirthalli, Basavaraju, Gangadhar, & Pascual-Leone, 2014). Indeed, if the mirror neuron system is directly involved in the retrieval of the meaning of action verbs, we should find atypical performance in action verb understanding in these patients related to difficulties in the interpretation of visual actions.…”