The default mode network (DMN) is a set of brain regions active at rest and less active during many tasks, but these regions also show task-related increases. By combining activation likelihood estimation meta-analysis with the BrainMap database, core DMN regions were identified and their functional heterogeneity examined. Meta-analytic coactivation maps showed each region connects with both DMN and non-DMN areas. Behavioral domain analysis revealed that DMN subnetworks are differentially specialized: affective, perceptual, and motor-processing cliques were identified. The results provide a connectivity model of DMN interactions during diverse tasks.
Ketamine, given at subanesthetic doses to healthy volunteers, produces psychosis-like symptoms and reduces functional connectivity in the salience network, auditory network, and default mode network (DMN). Midazolam, a sedative, only reduces DMN connectivity. The pattern of connectivity deficits caused by ketamine positively correlates with the pattern seen in schizophrenia, whereas midazolam's effects do not. After subtracting midazolam's effects, the remaining ketamine-specific disconnectivity pattern still correlates with schizophrenia deficits. This suggests that ketamine's psychosis-like effects have a brain functional basis that overlaps with schizophrenia-related connectivity disruptions.