Studies on human visual motion perception mechanism using magnetoencephalography and functional magnetic resonance imagng

我们研究了表观运动知觉和二阶运动知觉的神经机制。当许多小点的图案后面跟着一个相同的图案，但所有的点都在一个方向上稍微移动时，人类就会感知到运动。利用这种刺激，我们试图阐明与这种明显运动知觉相关的神经活动的时间结构。在受试者进行辨向任务时，测量了不同位移量的随机点图案的磁响应。诱发运动的磁响应与诱发无运动的磁响应相比，在反应潜伏期不变的情况下，磁响应幅值发生了明显的变化，且有三个明显的峰。反应源总是在枕颞区。结果表明，脑磁图可以测量到脑内视运动知觉的神经活动，这种活动至少发生在刺激开始后110 ms，在人MT+中更为明显。移动的物体通常是通过亮度（一阶）线索看到的，而人类可以通过非亮度（二阶）线索感知物体的运动。与以前的病例报告相反，没有生理学研究阐明了参与一级和二级运动过程的皮层区域的明显差异。我们使用3-T功能磁共振研究了人类受试者与这两种类型的运动感知相关的大脑反应。我们发现，颞上沟（STS）后部对刺激呈现和MT/V5+的线索不变激活具有选择性的神经反应。一阶运动没有观察到STS的显著激活，即使它的可见度降低到与二阶运动相当的水平。STS代表了感知二阶运动的主要结构，尽管需要进一步的研究来阐明发生在该区域的确切神经过程。少

We investigated neural mechanisms underlying apparent motion perception and second-order motion perception. Humans perceive motion when numerous small dots pattern is followed by one of the same pattern but with all the dots shifted a little in one direction. Using this stimulus, we addressed to elucidate the temporal structure of the neural activity related to this apparent motion perception. The magnetic responses to the random-dot patterns with various amounts of shift were measured while the subjects were performing a direction discrimination task. A significant magnetic response amplitude change occurred with three distinct peaks when the response inducing apparent motion was compared with those inducing no motion without change in the response latencies. The response origin was always within the occipitotemporal area. The results indicate that the neural activity for the perception of apparent motion can be measured by MEG that occur at least 110 ms after the stimulus onset possi … More bly in the human MT+.While moving objects are usually seen using luminance (first-order) cues, humans can perceive the motion of objects via non-luminance (second-order) cues. Contrary to previous case reports, no physiological studies have elucidated distinct differences in the cortical regions involved in first- and second-order motion processes. We investigated brain responses related to these two types of motion perception in human subjects using 3-T functional magnetic resonance. We found a selective neural response to various second-order motions in the posterior part of the superior temporal sulcus (STS) contralateral to stimulus presentation and cue-invariant activation of MT/V5+. No significant activation in the STS was observed by the first-order motion, even when its visibility was reduced to levels comparable to that of second-order motion. The STS represents the cardinal structure for perception of second-order motions, although further studies are needed to elucidate the exact neural process occurring in this area. Less