ESTIMATES OF VISUALLY EVOKED CORTICAL CURRENTS
ESTIMATES OF VISUALLY EVOKED CORTICAL CURRENTS
复制标题
DOI：
10.1016/0013-4694(92)90172-e
复制
发表时间：
1992-03-01
期刊：
影响因子：
--
通讯作者：
HAMALAINEN, MS
中科院分区：
文献类型：
--
作者：
AHLFORS, SP;ILMONIEMI, RJ;HAMALAINEN, MS
我们已经测量了磁场诱发的棋盘状扇形图案出现在16个位置附近的中心的视野。小刺激（< 2度），尽管如此，它给出了足够强的反应，使源定位，被用来限制皮层激活到一个小的区域，从而简化了磁场数据的分析。我们专注于优化实验设计：皮质源可以从我们的24通道磁力计的一个位置的测量中定位，并且只需重复刺激15-20次。即使是一个单一的响应计算的最小范数估计地图显示了可重复的功能，目前的分布，这是，80-100毫秒后的模式发作，视网膜组织在枕叶。由于脑磁图可以显示皮层的位置与2-3毫米的精度，我们的程序似乎有希望为进一步研究皮层视网膜病变和视野缺损。
We have measured magnetic fields evoked by the onset of checkerboard-like sectorial patterns presented at 16 locations near the center of the visual field. Small stimuli (< 2-degrees), which, nevertheless, gave sufficiently strong responses to enable source localization, were used to limit cortical activation to a small area, thus simplifying the analysis of the magnetic field data. We focused on optimizing the experimental design: cortical sources could be located from measurements at just one position of our 24-channel magnetometer and with as few as 15-20 repetitions of the stimulus. Minimum-norm-estimate maps calculated from even a single response showed reproducible features of the current distribution, which was, 80-100 msec after the pattern onset, retinotopically organized in the occipital lobe. Since magnetoencephalography can reveal cortical locations with a precision of 2-3 mm, our procedure appears promising for further studies of cortical retinotopy and visual field defects.