Transcranial magnetic stimulation of the occipital pole interferes with verbal processing in blind subjects.
Recent neuroimaging studies in blind persons show that the occipital cortex, including the primary visual cortex (V1), is active during language-related and verbal-memory tasks. No studies, however, have identified a causal link between early visual cortex activity and successful performance on such tasks. We show here that repetitive transcranial magnetic stimulation (rTMS) of the occipital pole reduces accuracy on a verb-generation task in blind subjects, but not in sighted controls. An analysis of error types revealed that the most common error produced by rTMS was semantic; phonological errors and interference with motor execution or articulation were rare. Thus, in blind persons, a transient 'virtual lesion' of the left occipital cortex interferes with high-level verbal processing
Amedi
Amir
A
Neurobiology Department, Life Science Institute and Interdisciplinary Center for Neural Computation, Hebrew University, Jerusalem 91904, Israel.
Floel
Agnes
A
Knecht
Stefan
S
Zohary
Ehud
E
Cohen
Leonardo G
LG
D000704:Analysis of Variance; D001766:Blindness / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009778:Occipital Lobe / Q000528:radiation effects*; D011930:Reaction Time / Q000528:radiation effects; D012660:Semantics; D050781:Transcranial Magnetic Stimulation; D014706:Verbal Learning / Q000502:physiology / Q000528:radiation effects*; D019987:Persons with Visual Disabilities