Highlights Somatosensory evoked potentials reveal reduced embodiment of emotions in autism Previous research has highlighted the contributions of the somatosensory system to emotion processing in typically developing (TD) individuals, but less is known about how this mechanism functions in the context of autism (ASD). To investigate the dynamics of somatosensory activity during emotion processing, we recorded EEG activity from two groups of individuals with ASD or TD while they performed a facial emotion discrimination task and a gender control task. In 50% of trials, we evoked somatosensory activity by tactile touches to participants’ fingers, 105 ms after the onset of the visual stimulus, and isolated somatosensory activity by subtracting the visual responses from the activity evoked by the visual and somatosensory stimuli. . Participants with ASD showed a selective reduction of SEP (P100) amplitudes, but not VEPs, compared to TD during the emotion task. Interestingly, autistic traits significantly predicted evoked SEP amplitudes during the emotion task. Our study provides direct evidence for reduced recruitment of the somatosensory system during emotion discrimination in ASD and suggests that this effect is not a byproduct of differences in visual processing. |
Consistent with current models of embodied emotions , this study investigates whether the somatosensory system shows reduced sensitivity to facial emotional expressions in autistics compared to neurotypical individuals, and whether these differences are independent of between-group differences in visual processing. of facial stimuli.
To investigate the dynamics of somatosensory activity beyond visual entrainment effects, we recorded EEG activity from two groups of people with autism spectrum disorder (ASD) or typically developing (TD) (men and women), while they performed a facial emotion discrimination task and a gender control task.
To probe the state of the somatosensory system during face processing, on 50% of the trials we evoked somatosensory activity using task-irrelevant tactile touches to the participants’ index finger, 105 ms after the onset of the visual stimulus. Importantly, we isolated somatosensory activity from concurrent visual activity by subtracting visual responses from activity evoked by somatosensory and visual stimuli.
The results revealed significant differences between task-dependent groups in the mid-latency components of somatosensory evoked potentials (SEP). Participants with ASD showed a selective reduction of SEP (P100) amplitudes compared to TD during the emotion task; and TD, but not ASD, showed greater somatosensory responses during emotion compared to gender discrimination.
Interestingly, autistic traits, but not alexithymia, significantly predicted evoked SEP amplitudes during the emotion, but not gender, task. Importantly, we did not observe the same pattern of group differences in visual responses.
Our study provides direct evidence for reduced recruitment of the somatosensory system during emotion discrimination in ASD and suggests that this effect is not a byproduct of differences in visual processing.
Meaning
The somatosensory system is involved in the embodiment of visually presented facial expressions of emotion. Although autism is characterized by difficulties in emotion-related processing, no studies have addressed whether this extends to embodied representations of others’ emotions.
By dissociating somatosensory activity from visual evoked potentials, we provide the first evidence for reduced recruitment of the somatosensory system during emotion discrimination in autistic participants, independent of differences in visual processing between typically developing and autism spectrum disorder participants. .
Our study uses a novel methodology to reveal the neural dynamics underlying emotion recognition difficulties in autism spectrum disorder and provides direct evidence that embodied simulation of others’ emotional expressions operates differently in autistic people. .
