rTMS to the right inferior parietal lobule disrupts self–other discrimination

TLDR

Self–other discrimination is fundamental to social interaction, but the neural systems underlying this ability are poorly understood. The study aimed to test whether the right inferior parietal lobule is necessary for discriminating self‑faces from familiar others. The authors used image‑guided 1 Hz rTMS to create a virtual lesion over the right IPL. 1 Hz rTMS to the right IPL selectively disrupted self‑other discrimination, whereas stimulation of the left IPL had no effect, demonstrating a causal role for the right IPL in this high‑level cognitive capacity.

Abstract

Self–other discrimination is fundamental to social interaction, however, little is known about the neural systems underlying this ability. In a previous functional magnetic resonance imaging study, we demonstrated that a right fronto-parietal network is activated during viewing of self-faces as compared with the faces of familiar others. Here we used image-guided repetitive transcranial magnetic stimulation (rTMS) to create a 'virtual lesion' over the parietal component of this network to test whether this region is necessary for discriminating self-faces from other familiar faces. The current results indeed show that 1 Hz rTMS to the right inferior parietal lobule (IPL) selectively disrupts performance on a self–other discrimination task. Applying 1 Hz rTMS to the left IPL had no effect. It appears that activity in the right IPL is essential to the task, thus providing for the first time evidence for a causal relation between a human brain area and this high-level cognitive capacity.