The neural network associated with lexical-semantic knowledge about social groups.

A person can be appraised as an individual or as a member of a social group. In the present study we tested whether the knowledge about social groups is represented independently of the living and non-living things. Patients with frontal and temporal lobe tumors involving either the left or the right hemisphere performed three tasks--picture naming, word-to-picture matching and picture sorting--tapping the lexical semantic knowledge of living things, non-living things and social groups. Both behavioral and voxel-based lesion-symptom mapping (VLSM) analyses suggested that social groups might be represented differently from other categories. VLSM analysis carried out on naming errors revealed that left-lateralized lesions in the inferior frontal gyrus, amygdala, insula and basal ganglia were associated with the lexical-semantic processing of social groups. These findings indicate that the social group representation may rely on areas associated with affective processing.