Autistic traits predict poor integration between top-down contextual expectations and movement kinematics during action observation

Abstract

Autism is associated with difficulties in predicting and understanding other people's actions. There is evidence that autistic traits are distributed across a spectrum and that subclinical forms of autistic impairments can also be measured in the typical population. To investigate the association between autistic traits and motor responses to others' actions, we quantified these traits and measured cortico-spinal excitability modulations in M1 during the observation of actions embedded in congruent, incongruent and ambiguous contexts. In keeping with previous studies, we found that actions observed in congruent contexts elicited an early facilitation of M1 responses, and actions observed in incongruent contexts, resulted in a later inhibition. Correlational analysis revealed no association between autistic traits and the facilitation for congruent contexts. However, we found a significant correlation between motor inhibition and autistic traits, specifically related to social skills and attention to details. Importantly, the influence of these factors was independent from each other, and from the observer's gender. Thus, results suggest that individuals with higher social deficits and greater detail-processing style are more impaired in suppressing action simulation in M1 when a mismatch between kinematics and context occurs. This points to difficult integration between kinematics and contextual representations in the autistic-like brain.

Figure 1

Examples of stimuli and conditions. Depending on the action, the reach-to-grasp movement kinematics was different in terms of precision vs. whole-hand grips. In addition, the actions could be performed in three different contexts: congruent, incongruent, and ambiguous.

Figure 2

Behavioural results. Participants’ performance in predicting the course of the observed actions (expressed as d’) during the 3 action observation conditions (Congruent, Incongruent, and Ambiguous) at the 2 time-windows (early, late). Data points represent individual participants. Asterisks indicate significant comparison (p < 0.05). Error bars represent SEM and dotted lines MEAN.

Figure 3

MEPs results. Amplitudes of MEPs recorded from the FDI (a) and ECR (b) muscles during the 3 action observation conditions (Congruent, Incongruent, and Ambiguous) at the 2 time-windows (early, late). Data points represent individual participants. Asterisks indicate significant comparison (p < 0.05). Error bars represent SEM and dotted lines MEAN.

Figure 4

Pearson correlation results. Scatter plots illustrating the relationship between Facilitatory (Congruent – Ambiguous) and Inhibitory (Incongruent – Ambiguous) MEP indexes and the AQ total scores at the 2 time-windows (early, late).