Modulating interoception by insula stimulation: A double-blinded tDCS study

Interoception consists in the perception and processing of internal body signals, such as heartbeat. Previousneuroimaging studies revealed that attention to heartbeat activated bilateral insula and premotor regions.In the present double-blind study, we aimed at testing the role of insula in interoception by means of tran-scranial direct current stimulation (tDCS) interfering with its activity.Sixteen healthy participants responded to a questionnaire to evaluate the tendency to be internally focusedand performed a heartbeat counting task before and after tDCS in three sessions (left insula stimulation, rightinsula stimulation, sham stimulation). Real and reported heartbeat were recorded and used to calculate theaccuracy scores.A significant interaction between stimulation condition and time (pre- and post-stimulation) was found due toa significant improvement of the interoceptive accuracy in the sham condition only.Our results demonstrated that stimulation over the insula reduced the possibility to improve the precisionwith which individuals detect internal signals.