Task-Related Aperiodic EEG (1/f) Activity in Autism

Autism has been hypothesized to involve atypicalities in the balance between neural excitation and inhibition (E/I). Aperiodic EEG activity, characterized by the 1/f exponent of the power spectrum, provides a proxy of cortical E/I dynamics. However, prior studies in autism report mixed findings regarding the slope of aperiodic activity. One potentially important modulator of EEG slope is task engagement. Here, we examined variations in aperiodic slopes in autistic (n = 35) and neurotypical (n = 39) adults during passive viewing and an active, goal-directed task. The data revealed that autistic participants exhibited steeper slopes (indicative of increased inhibition vs. excitation) during the active task relative to passive viewing, whereas neurotypical participants showed no significant task-related changes. These findings suggest that aperiodic activity reflects dynamic, task-dependent neural adaptation rather than baseline group differences. Task engagement may reveal compensatory inhibitory processes in autistic adults, underscoring the importance of considering task demands and individual variability when investigating E/I balance in autism.