Epstein C M, Verson R, Zangaladze A
Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA.
J Clin Neurophysiol. 1996 May;13(3):247-52. doi: 10.1097/00004691-199605000-00009.
Perception of extrafoveal visual targets can be suppressed by magnetic stimulation over the occipital lobes, but the site of interference for this and similar phenomena has not been well defined. We modified a previously used technique to determine the locus of magnetic activation. Using butterfly stimulus coils of different sizes and electric field profiles, we determined a scalp position of minimum threshold and a level of stimulator output that produced 50% error rates for each coil. Intersection of the corresponding electric field profiles in air and in a saline model head was similar and identified superficial occipital cortex rather than the primary visual area as the site of perceptual suppression. Less direct analyses involving the distribution of induced electric fields produced the same conclusion. These results suggest specific hypotheses about the effects of magnetic stimulation on visual physiology.
枕叶的磁刺激可抑制对中央凹外视觉目标的感知，但这种现象及类似现象的干扰部位尚未明确界定。我们改进了之前使用的技术来确定磁激活位点。使用不同尺寸和电场分布的蝶形刺激线圈，我们确定了每个线圈产生最小阈值的头皮位置以及产生50%错误率的刺激器输出水平。空气和生理盐水模型头部中相应电场分布的交点相似，并确定枕叶皮质表面而非初级视觉区为感知抑制位点。涉及感应电场分布的不太直接的分析也得出了相同的结论。这些结果提出了关于磁刺激对视觉生理学影响的具体假设。
