Magnetic stimulation of visual cortex: factors influencing the perception of phosphenes.
Magnetic stimulation of visual cortex: factors influencing the perception of phosphenes.
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视觉皮层的磁刺激：影响光幻视感知的因素。
DOI：
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发表时间：
1998
影响因子：
2.4
通讯作者：
L. Day
中科院分区：
文献类型：
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作者：
P. G. Ray;K. Meador;C. Epstein;D. Loring;L. Day
作者利用枕叶皮层经颅磁刺激，研究了健康志愿者产生光幻视的刺激参数。单脉冲或刺激列车容易引起光幻视在所有科目。引起感知光幻视所需的阈值电流对于长度从250毫秒到2000毫秒的刺激序列基本上是相同的，但是对于持续时间较短的序列显著增加。刺激频率的影响是可变的，每个受试者都有一个独特的“频率调谐曲线”，但总体而言，产生光幻视所需的阈值电流随着刺激频率的增加而降低。使用成对的脉冲，感知阈值是平坦的刺激间隔2毫秒和100毫秒之间，但迅速增加的刺激间隔增加到100毫秒以上。刺激中线外侧的部位在对侧视野中引起光幻视。光幻视在视野的下部和周边方面占主导地位。研究结果进行了讨论，在有关类似的研究电刺激的躯体感觉皮层。
Using transcranial magnetic stimulation of occipital cortex, the authors studied the stimulus parameters that generate phosphenes in healthy volunteers. Single pulses or trains of stimuli readily elicited phosphenes in all subjects. The threshold current needed to elicit perception of phosphenes was essentially the same for stimulus trains from 250 msec to 2000 msec in length, but increased dramatically for trains of shorter duration. The effect of stimulus frequency was variable, with each subject having a distinctive "frequency tuning curve," but overall, the threshold current necessary to produce phosphenes decreased as frequency of stimulation increased. Using paired pulses, the perceptual threshold was flat for interstimulus intervals between 2 msec and 100 msec, but increased rapidly as the interstimulus interval was increased above 100 msec. Stimulation of sites lateral to the midline elicited phosphenes in the contralateral visual field. Phosphenes were dominant in the lower and peripheral aspects of the visual fields. The findings are discussed in relation to similar studies of electrical stimulation of somatosensory cortex.