Moon So Young, Barton Jason J S, Mikulski Szymon, Polli Frida E, Cain Matthew S, Vangel Mark, Hämäläinen Matti S, Manoach Dara S
Department of Neurology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
Neuroimage. 2007 Jul 15;36(4):1313-23. doi: 10.1016/j.neuroimage.2007.04.040. Epub 2007 Apr 27.
To perform a saccadic response to a visual stimulus, a 'sensorimotor transformation' is required (i.e., transforming stimulus location into a motor command). Where in the brain is this accomplished? While previous monkey neurophysiology and human fMRI studies examined either parietal cortex or frontal eye field, we studied both of these regions simultaneously using magnetoencephalography (MEG). Nineteen healthy participants performed a pseudorandom series of prosaccades and antisaccades during MEG. Antisaccades require a saccade in the direction opposite a suddenly appearing stimulus. We exploited this dissociation between stimulus and saccadic direction to identify cortical regions that show early activity for a contralateral stimulus and late activity for a contralateral saccade. We found that in the left hemisphere both the intraparietal sulcus and the frontal eye field showed a pattern of activity consistent with sensorimotor transformation - a transition from activity reflecting the direction of the stimulus to that representing the saccadic goal. These findings suggest that sensorimotor transformation is the product of coordinated activity across the intraparietal sulcus and frontal eye field, key components of a cortical network for saccadic generation.
要对视觉刺激做出快速眼跳反应，需要进行“感觉运动转换”（即将刺激位置转换为运动指令）。大脑中的哪个部位完成这一过程呢？虽然之前的猴子神经生理学和人类功能磁共振成像研究只考察了顶叶皮质或额叶眼区，但我们使用脑磁图（MEG）同时研究了这两个区域。19名健康参与者在脑磁图检查期间进行了一系列伪随机的同向眼跳和反向眼跳。反向眼跳要求朝与突然出现的刺激相反的方向进行眼跳。我们利用刺激方向和眼跳方向之间的这种差异，来识别对侧刺激时显示早期活动以及对侧眼跳时显示晚期活动的皮质区域。我们发现，在左半球，顶内沟和额叶眼区均显示出与感觉运动转换一致的活动模式——从反映刺激方向的活动转变为代表眼跳目标的活动。这些发现表明，感觉运动转换是顶内沟和额叶眼区协同活动的产物，而这两个区域是眼跳产生的皮质网络的关键组成部分。
