The association between resting state aperiodic activity and Research Domain Criteria Social Processes in young neurotypical adults

The aperiodic exponent of the electrophysiological signal has been utilised to demonstrate differences in brain excitation-inhibition in ageing, cognition, and neuro- and psycho-pathology. Furthermore, excitation-inhibition imbalance has been associated with social communication difficulties in clinical and non-clinical cohorts. No work to date, however, has explored the association between aperiodic activity and social communication difficulties. A total of 40 neurotypical young adults aged 18-24 (24 female; age mean = 21.6, SD = 1.9) each underwent 5 minutes of eyes open and eyes closed resting state electroencephalography using a 64-channel HydroCel Geodesic Sensor Net. Participants also completed Research Domain Criteria social processes measures: Social Responsiveness Scale, Reading the Mind in the Eyes task, and Penn Emotional Recognition Task. Sex differences in aperiodic exponent and offset were observed, with larger exponent and greater offset observed in males, suggestive of greater inhibitory tone. Whole-brain, as well as left and right social brain, aperiodic exponent were moderately correlated with Social Responsiveness Scale Social Communication Index, but not Reading the Mind in the Eyes or Penn Emotional Recognition tasks. However, the correlations between aperiodic exponent and Social Responsiveness Scale Social Communication Index did not survive multiple comparisons correction, and regression models demonstrated that neither aperiodic exponent or offset were significantly predictive of social processes outcomes. These preliminary data provide some evidence that increased aperiodic activity may be associated with social communication difficulties, however, larger samples are needed to validate these initial findings.