Background: Repetitive transcranial magnetic stimulation (rTMS) at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a "virtual lesion" in stimulated brain regions, with correspondingly diminished behavioral performance.
Methodology/principal Findings: Here we investigated the effects of rTMS to visual cortex on subjects' ability to perform visual psychophysical tasks.