Fig. 2

Connections of brain regions implicated in both social and repetitive behaviors. Activation of projection from the amygdala to the hippocampus increases repetitive self-grooming behavior, yet decreasing social behaviors [61]. Optogenetic disruption of E/I balance of the PFC impairs social behaviors [77]. Inhibition of the PFC projection to the VTA reduces repetitive behaviors and activation of the projection from the PFC to the SNc induces hyperactivity [72, 81]. Dopaminergic projections from the VTA to the ventral striatum, a key region implicated in motivation is necessary for social reward [82]. SNc substantia nigra pars compacta, PFC prefrontal cortex, VTA ventral tegmental area