Modulating the left-hemifield bias in rapid serial visual presentation by repetitive transcranial magnetic stimulation
Smigasiewicz, K.1, Verleger, R.1, Möller, F.1, Kuniecki, M.2, Groppa, S.3, and Siebner, H. R.3
1Department of Neurology, University of Lübeck; 2Institute of Psychology, Jagiellonian University, Krakow, Poland; 3Department of Neurology, Christian-Albrecht-University of Kiel
In the two-stream RSVP task left target are better identified possibly reflecting dominance of the right hemisphere. If so, rTMS to right parietal cortex might boost left hemisphere performance for right hemifield targets, by weakening right-hemispheric control. In Experiment 1, the left-hemifield advantage was smaller with rTMS applied at the right than at the left parietal cortex. However, the mechanism of this influence was not clear. Therefore, in the two next experiments, performance with rTMS and sham-rTMS was compared within-subjects, either at the right hemisphere (Experiment 2) or at the left hemisphere (Experiment 3). Only in Experiment 3, rTMS deteriorated identification of the right-side targets. Thus, it seems that only the nondominant left parietal cortex can be perturbed by rTMS in this task resulting in increased left-hemifield bias.