Vaina L M, Cowey A, Kennedy D
Department of Biomedical Engineering and Neurology, Boston University and Harvard Medical School, Brigham and Women's Hospital, Massachusetts 02215, USA.
Hum Brain Mapp. 1999;7(1):67-77. doi: 10.1002/(SICI)1097-0193(1999)7:1<67::AID-HBM6>3.0.CO;2-K.
An unresolved issue in visual motion perception is how distinct are the processes underlying "first-order" and "second-order" motion. The former is defined by spatiotemporal variations of luminance and the latter by spatiotemporal variations in other image attributes, such as contrast or depth. Here we describe two neurological patients with focal unilateral lesions whose contrasting perceptual deficits on psychophysical tasks of "first-order" and "second-order" motion are related to the maps of the human brain established by functional neuroimaging and gross anatomical features. We used a relatively fine-grained neocortical parcellation method applied to high-resolution MRI scans of the patients' brains to illustrate a subtle, yet highly specific dissociation in the visual motion system in humans. Our results suggest that the two motion systems are mediated by regionally separate mechanisms from an early stage of cortical processing.
视觉运动感知中一个尚未解决的问题是，“一阶”和“二阶”运动背后的过程有多大区别。前者由亮度的时空变化定义，后者由其他图像属性（如对比度或深度）的时空变化定义。在这里，我们描述了两名患有局灶性单侧病变的神经学患者，他们在“一阶”和“二阶”运动的心理物理学任务上形成对比的感知缺陷与通过功能神经成像和大体解剖特征建立的人类大脑图谱相关。我们使用一种相对精细的新皮质分区方法，应用于患者大脑的高分辨率MRI扫描，以说明人类视觉运动系统中一种微妙但高度特异性的分离。我们的结果表明，这两种运动系统从皮质处理的早期阶段就由区域上分离的机制介导。
