Suppression of vision by transcranial magnetic stimulation: a third mechanism

We recently reported three periods when single-pulse transcranial magnetic stimulation (TMS) of the occipital pole impaired performance on a forced-ch oice visual letter-identification task. TMS-induced suppression during thes e periods is best explained by a blink-associated covering of the pupils an d by a direct interference with letter-processing neural activity. We now r eport TMS-induced suppression at times that seem too late for the suppressi on to be explained by the first mechanism and too early for the suppression to be explained by the second mechanism. The most likely explanation is a blink-associated interference with letter-processing neural activity. Neuro Report 11:2345-2349 (C) 2000 Lippincott Williams & Wilkins.