Interactive Social Neuroscience to Assess Resting State Brain Activity in the Broad Autism Phenotype

Background: Autism Spectrum Disorder (ASD) is hallmarked by interpersonal difficulties, yet there is limited research examining brain activity during actual social interactions. To investigate this issue, this study utilized interactive social neuroscience methods to examine alpha oscillations (8-11 Hz) measured with electroencephalography (EEG) in social context and associations between brain activity and autistic traits in typically developing (TD) pairs of adults.

Objectives:  Characterize neural markers of resting brain activity during an interpersonal interaction and their association with autistic traits in a social context.

Methods:  16 TD adults, grouped in same-sex dyads, sat quietly for two minutes with their eyes opened (EO) and eyes closed (EC) in three conditions: (1) “separate” rooms, (2) the same room with their “backs” to each other, and (3) the same room while “facing” each other. EEG was simultaneously recorded from each member of the dyad using wireless recording devices. The Autism Quotient (AQ) was administered to quantify social function and dysfunction.

Results:  For alpha power at frontal sites, a significant interaction between condition (separate, back, facing) and eyes (EO/EC) was detected (p=.017). Post-hoc paired samples t-tests indicated: (1) EO elicited greater alpha power than EC in the separate condition but not in back or facing conditions (p=.040); and (2) in the EO condition, greater alpha power in the separate condition than in the back condition (p=.040). Analysis then examined alpha power in each individual frontal electrode; only significant findings are reported. There was a main effect of eyes at left frontal (FL; F(1,12)=5.864, p=.032), Fz (F(1,12)=6.810, p=.023), and right frontal (FR; F(1,12)=5.748, p=.034) sites. There was also a main effect of condition at FL (F(1.1, 13.4)=5.404, p=.033), Fz (F(1.2,15.2)=6.969, p=.014), and FR (F(1.3,15.3)=6.268, p=.018). Pairwise comparisons revealed greater alpha power in EC than EO in FL (p=.032), Fz (p=.023), and FR (p=.034), as well as attenuated alpha power in facing compared to back (FL, p=.013, Fz, p=.044) and separate (FL, p=.021; Fz, p=.010; FR, p=.014) conditions. Further, the difference in alpha power between separate and back with EO in FL (p=.015) and separate and facing with EO in FR (p=.048) was correlated with the attention switching subscale of the AQ. Additionally, scores on the attention to details subscale of the AQ were associated with the difference in alpha power between separate and back conditions with EC in FL (p=.011) and FR (p=.002) and separate and facing conditions with EC in FL (p=.023) and FR (p=.018).

Conclusions:  This study applied interactive social neuroscience to investigate the relationship between autistic traits and resting EEG activity during varying levels of interpersonal interaction. Results reveal that the presence of another person modulates resting brain activity. Individuals with lower levels of autistic traits exhibited greater alpha power when resting separately compared to when resting with another person, suggesting greater sensitivity to the presence of another person. Our findings provide new insight into modulation of resting state brain activity through the presence of another person and emphasize the importance of utilizing more ecologically-valid approaches in neuroscientific studies of social brain function.