Repetitive Transcranial Magnetic Stimulation (rTMS) over Dorsal Premotor Areas Interferes with Visuospatial Attention

The present study used repetitive transcranial magnetic stimulation (rTMS) to investigate interference of the dorsal premotor cortex (PMd) during a spatial serial prediction task (SPT). Using a 3×2 design, rTMS was applied either targeting the right or left PMd, or a sham position in the vicinity of the occipital pole (factor SITE), and either during the early sequence encoding phase or during the late sequence deviant monitoring phase (factor TIME). Estimated stimulation sites over the target areas were determined individually using anatomical MRI scans. Performance was assessed by difference of error scores between the SPT and a neutral baseline task. Performance was found to be impaired in early-right vs. early-left, and in late-left vs. early-left stimulation. Our findings confirm that rTMS over PMd can cause behavioral impairments in an SPT. Moreover, the specific affects suggest different functional roles of right and left PMd in encoding and deviant monitoring in perceptual sequences.