The role of the left inferior frontal gyrus in social perception: An rTMS study

Perceiving and interpreting social information richness is something that humans do automatically whenever they engage in social interactions. Numerous studies have identified neural substrates, including mirror neurons that may enable such social perception. In this study, we temporarily disrupted activity in the left inferior frontal gyrus (LIFG) using repetitive transcranial magnetic stimulation (rTMS). We investigated whether this cortical region, that is hypothesized to include mirror neurons, plays a central role in social perception. The LIFG was stimulated in the experimental condition (n = 18), the vertex was targeted in the control condition (n = 19). Disrupting LIFG, but not vertex, increased reaction times during an emotion recognition task, and eliminated the suppression of the 8–12 Hz EEG μ rhythm, postulated as an index of mirroring activity. The results of this study provide further evidence for the role of the human mirror neuron system (MNS) in social perception, and indicate that the MNS can be measured with EEG.

Research Highlights
► Social cognition is dissociable from social perception.
► rTMS over the LIFG disrupted social perception but not social cognition.
► Mu (8–13 Hz) but not SMR (12–15 Hz) rhythms are an index of mirroring activity.