鸽子丘脑圆核(N.Rotundus)的机能亚区

FUNCTIONAL SUBDIVISIONS IN THE PIGEON'S THALAMUS NUCLEUS ROTUNDS

研究鸽子丘脑圆核细胞对背景光照度、颜色和计算机产生的小圆和长方形靶,噪声点纹理图形和三度空间运动刺激反应。系统的电极尖端标志点显示该核有4个特殊的机能亚区,5种机能细胞分别集聚在这些亚区中。绝大多数从背前亚区记录的细胞选择特定的颜色发生反应;从背中亚区记录的细胞其发放速度则明显地被整个感受野照度所调制;背后亚区集聚了全部3D运动细胞,它们选择深度方向的运动物体反应。集聚在腹侧亚区的细胞对小运动物体反应强烈,此反应有兴奋的也有抑制的。这些结果表明,颜色、照度、3D运动和在正切平面上2D运动的信息,在鸟类丘脑圆核水平分别进入特定的亚区进行加工处理。

The responses of single cells to colour, luminance, and computer-generated spots, bars, kinematograms, and motion-in-depth stimuli were studied in the nucleus rotun-dus of pigeon's thalamus. Systematic electrode penetrations revealed that there are four functionally distinct subdivisions within rotundus where five classes of visual selective cells were clustered. Most cells recorded from the dorsal-anterior subdivision responded selectively to the colour of the stimulus. The firing rate of the cells in dorsal central subdivision, however , is dramatically modulated by changing the level of illumination over the whole visual field. There is almost all 3D-movtion cells in the dorsal-posterior subdivision of the nucleus. They respond selectively to motion-in depth (i. e. an expending or .contracting figures in the visual field). Cells in the ventral subdivision strongly respond to moving occlusion edges and very small moving objects, with either excitatory or inhibitory responses. These results indicate that visual information processing of colour, ambient illumination, and motion-in-depth are segregated into different subdivisions at the level of nucleus rotundus in the avian's thalamus, Supported by NSERC grants to B. J. F.