Phosphenes and transient scotomas induced by magnetic stimulation of the occipital lobe: their topographic relationship Export

@article{citeulike:2282487, abstract = {Transcranial magnetic stimulation (TMS) of the visual cortex is known to induce phosphenes and is able to suppress visual perception. To address the topographic relationship of phosphenes and transient scotomas, the visual field of 10 normal subjects was investigated using a perimetric approach. The central visual field (diameter: 20[degree sign]) was tested at 32 sites. Perceptual thresholds were determined by presenting 1 ms test spots flashed with varying intensity in random order. TMS was applied with a focal figure-of-eight coil placed over the inion. All subjects perceived phosphenes, mostly restricted to one of the lower quadrants within the visual field. In 13 out of 15 investigations, a magnetic stimulus triggered 100 ms after the visual target resulted in a relative scotoma with threshold changes of 8 dB or more. In 9 of 13 investigations, scotomas coincided spatially with sketches of phosphenes made by subjects in a separate test. Scotomas covered only a small percentage of the total visual field, which may explain the failure of previous studies to find perceptual suppression with the focal coil. The present result demonstrates that phosphenes evoked during TMS can serve as a guide for optimal visual stimulus alignment in neuropsychological experiments.}, author = {Kammer, Thomas}, citeulike-article-id = {2282487}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/S0028-3932(98)00093-1}, citeulike-linkout-1 = {http://www.sciencedirect.com/science/article/B6T0D-3VM6JW8-7/2/19f6f27e7d8bf62cab0b720891245668}, day = {1}, doi = {10.1016/S0028-3932(98)00093-1}, journal = {Neuropsychologia}, keywords = {phosphene, scotoma, tms, tms-figure8-coil, tms-single-pulse}, month = {November}, number = {2}, pages = {191--198}, posted-at = {2008-01-23 23:43:50}, priority = {2}, title = {Phosphenes and transient scotomas induced by magnetic stimulation of the occipital lobe: their topographic relationship}, url = {http://dx.doi.org/10.1016/S0028-3932(98)00093-1}, volume = {37}, year = {1998} }

TY - JOUR ID - citeulike:2282487 L3 - citeulike-article-id:2282487 N2 - Transcranial magnetic stimulation (TMS) of the visual cortex is known to induce phosphenes and is able to suppress visual perception. To address the topographic relationship of phosphenes and transient scotomas, the visual field of 10 normal subjects was investigated using a perimetric approach. The central visual field (diameter: 20[degree sign]) was tested at 32 sites. Perceptual thresholds were determined by presenting 1 ms test spots flashed with varying intensity in random order. TMS was applied with a focal figure-of-eight coil placed over the inion. All subjects perceived phosphenes, mostly restricted to one of the lower quadrants within the visual field. In 13 out of 15 investigations, a magnetic stimulus triggered 100 ms after the visual target resulted in a relative scotoma with threshold changes of 8 dB or more. In 9 of 13 investigations, scotomas coincided spatially with sketches of phosphenes made by subjects in a separate test. Scotomas covered only a small percentage of the total visual field, which may explain the failure of previous studies to find perceptual suppression with the focal coil. The present result demonstrates that phosphenes evoked during TMS can serve as a guide for optimal visual stimulus alignment in neuropsychological experiments. IS - 2 JF - Neuropsychologia EP - 198 TI - Phosphenes and transient scotomas induced by magnetic stimulation of the occipital lobe: their topographic relationship VL - 37 SP - 191 KW - phosphene KW - scotoma KW - tms KW - tms-figure8-coil KW - tms-single-pulse AU - Kammer, Thomas PY - 1998/11/01/ UR - http://dx.doi.org/10.1016/S0028-3932(98)00093-1 ER -