Nakamura Y, Ohtsuka K
Department of Ophthalmology, School of Medicine, Sapporo Medical University, Japan.
Jpn J Ophthalmol. 1999 Jan-Feb;43(1):36-43. doi: 10.1016/s0021-5155(98)00053-7.
The middle temporal (MT) area of the cortex of the monkey is involved in visual motion analysis. Previous studies using brain-imaging techniques have shown that the area around the anterior occipital cortex in man is homologous to the area MT of the monkey. In this study, we investigated the cortical components of motion-triggered visual evoked potentials and their topography in the visual cortex of man.
Visual evoked potentials to the onset of a visual motion stimulus (m-VEPs) were recorded from 5 normal subjects aged 25 to 34 years. A random dot pattern was used as the stimulus for the m-VEPs. The dots moved horizontally to the right and then to the left alternately for 500 milliseconds with interstimulus intervals of 1500 milliseconds. The speed of motion was varied in five steps from 5-25 degrees/s. Fifteen electrodes were placed on the occiput around O(z) at 5-cm intervals. Color contour maps showing the distribution of voltage over the 15 electrodes at latencies ranging from 0-200 milliseconds with a 20-millisecond interval were made for each subject. These were coregistered with three-dimensional magnetic resonance images of the same brain to specify the topography of the main components of the m-VEPs in relation to the sulcal and gyral pattern of the visual cortex.
We consistently observed a positive wave with a peak latency of about 100 milliseconds (P100) and a negative wave with a peak latency of about 150 milliseconds (N150) for all subjects. Topographical analysis showed that P100 was dominant in a relatively wide area caudal to O(z), whereas N150 was dominant in a relatively small area posterior to the right anterior occipital sulcus, which included the area corresponding to the area MT in man.
These findings suggest that N150 represents the activity of the area MT in the human visual cortex related to motion perception.
猴子大脑皮层的颞中区（MT）参与视觉运动分析。以往使用脑成像技术的研究表明，人类枕叶前部周围区域与猴子的MT区同源。在本研究中，我们调查了运动触发视觉诱发电位的皮层成分及其在人类视觉皮层中的地形图。
记录了5名年龄在25至34岁之间的正常受试者对视觉运动刺激开始时的视觉诱发电位（m-VEPs）。随机点模式用作m-VEPs的刺激。点以每秒5 - 25度的速度分五步变化，水平向右移动然后向左交替移动500毫秒，刺激间隔为1500毫秒。在枕骨围绕O(z)以5厘米间隔放置15个电极。为每个受试者制作了颜色等高线图，显示在0 - 200毫秒潜伏期内以20毫秒间隔的15个电极上的电压分布。这些图与同一大脑的三维磁共振图像进行配准，以确定m-VEPs主要成分相对于视觉皮层沟回模式的地形图。
我们在所有受试者中一致观察到一个峰值潜伏期约为100毫秒的正波（P100）和一个峰值潜伏期约为150毫秒 的负波（N150）。地形图分析表明，P100在O(z)尾侧的相对较宽区域占主导，而N150在右枕前沟后方的相对较小区域占主导，该区域包括人类中与MT区对应的区域。
这些发现表明，N150代表人类视觉皮层中与运动感知相关的MT区的活动。
