Resting-state brain connectivity and sociability: a whole-brain affair

Sociability is relevant for most mental health conditions and their prognosis. The classic "social brain" maps mainly to the default mode (DMN) and salience networks (SN). Recent studies also suggest involvement of other brain regions, but results are not yet fully consistent and interpretable. We conducted a fully data-driven resting-state connectivity study of sociability in the UK Biobank (N=31,266). BOLD amplitude within, and timeseries correlations between 21 intrinsic brain networks were associated with a general sociability metric. Sociability showed modest but significant associations with many resting-state functional connectivity measures throughout the brain. Sociability was positively associated with sensorimotor network connectivity and showed intricate association patterns with SN and DMN connectivity. Based on our results, we hypothesise that there are important, probably reciprocal links between social behaviours and sensorimotor networks, and that social isolation may be accompanied by thought processes within the DMN being isolated from the rest of the brain.