Studies on visual perception mechanism using magnetoenc ephalography

我们用脑磁图研究了脑外皮层响应视觉运动的个体间位置差异。记录了12名受试者从右颞枕区开始对视觉运动的磁反应。所有被试对明显或随机的点相干运动均有明显的反应。利用单等效电流偶极子模型研究了这些响应的起源。每个受试者离发源最近的头皮也被确定，这可能在经颅刺激研究中有用。虽然所有受试者的磁响应应具有相同的功能特性；由于神经活动只与运动的开始同步，估计的起源在受试者之间差异很大。根据在个体三维磁共振图像中调查的脑沟解剖结构，起源位置可分为三种类型之一：颞枕、枕或顶骨。7名受试者发现了颞枕型，解剖区域位于人类MT/V5附近。2名受试者为枕型，其解剖区位于MT/V5后，解剖区对应于V3A。其他3例患者的起源为顶骨型背吻侧至解剖MT/V5，区域位于颞上沟后端附近。尽管所有这些皮层区域似乎都与视觉运动的神经过程有关，但它们是否在功能上对应于相同的名称或迁移的MT/V5，现在必须确定。

We used magnetoencephalography to study inter-individual locational difference in the extrastriate region which responds to visual motion. Magnetic responses to visual motion onset from the right temporo-occipital area were recorded from 12 subjects. All the subjects had clear responses to apparent or random dot coherent motion. The origins of these responses was investigated by use of the single equivalent current dipole model. The nearest scalp to the origin also was identified for each subject, which may be useful in transcranial stimulation studies. Although the magnetic responses of all the subjects should have the same functional properties ; be related to neural activities synchronized exclusively to the onset of motion, the estimated origins varied greatly among the subjects. The location of origin could be classified as one of three types : temporo-occipital, occipital, or parietal, according to the sulcal anatomy investigated in the individual's three-dimensional magnetic resonance image. Temporo-occipital types were found for seven subjects, and anatomically the regions were around human MT/V5. Two subjects had the occipital type, with regions posterior to the anatomical MT/V5 and corresponding to V3A anatomically. The other three subjects had origins classified as the parietal type dorso-rostral to the anatomical MT/V5, with regions around the posterior end of the superior temporal sulcus. Although all these cortical regions appear to be related to the neural process of visual motion, whether they correspond functionally to the same names or migrated MT/V5 must now be determined.