Center-surround interactions in the middle temporal visual area of the owl monkey
Center-surround interactions in the middle temporal visual area of the owl monkey
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DOI：
10.1152/jn.2000.84.5.2658
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发表时间：
2000-11-01
影响因子：
2.5
通讯作者：
Born, RT
中科院分区：
文献类型：
--
作者：
Born, RT
采用微电极记录和2-脱氧葡萄糖（2dg）标记技术研究了猫头鹰猴颞叶中部视觉区（MT）中心-环绕相互作用。这些技术揭示了柱状神经元群，它们的接受野与移动的视觉刺激有相反类型的中心-环绕相互作用。在一种柱状图中，神经元对单条或点等物体反应良好，但对随机点等大型纹理刺激反应不佳。这通常是由于感受野具有拮抗环绕：环绕运动与中心抑制反应的偏好方向相同，从而使这些神经元对宽视场运动无反应。在第二组互补的，交错的柱中，神经元接受野有强化的周围，并对宽视场运动做出最佳反应。这种功能性组织不能用双目视差的系统性差异来解释。在这两种列类型中，与其他层相比，在输入层中发现的接受野表现出中心-周围相互作用的神经元较少。在单个单元上进行了额外的测试，以检查中心-环绕相互作用的性质。环绕的方向调谐比中心的方向调谐更宽，相对于中心的方向，首选方向倾向于相同或相反的方向，只有很少的方向是正交的。不同速度的环绕运动调节了对中心位置移动刺激的整体反应，但它不会产生中心调谐曲线的峰值在方向或速度上的变化。在局部运动处理列的第3B层和第5层中，许多神经元只对局部运动对比作出反应，但对视野区域的反应比最佳刺激大小大得多。这种感受野类型的中心特征是视网膜置换空间周围拮抗的普遍化，这一特性与前面描述的其他“复杂”感受野相似。不同类型的中心-环绕相互作用的柱状组织可能反映了视觉运动信息在视觉运动处理中作为互补功能的宽视场和局部运动对比系统的初始分离。这种分离似乎发生在猕猴运动处理流的后期阶段，即内侧颞上区（MST），并且在无脊椎动物视觉系统中也有描述，其中它似乎涉及区分背景运动和物体运动的重要功能。
Microelectrode recording and 2-deoxyglucose (2dg) labeling were used to investigate center-surround interactions in the middle temporal visual area (MT) of the owl monkey. These techniques revealed columnar groups of neurons whose receptive fields had opposite types of center-surround interaction with respect to moving visual stimuli. In one type of column, neurons responded well to objects such as a single bar or spot but poorly to large textured stimuli such as random dots. This was often due to the fact that the receptive fields had antagonistic surrounds: surround motion in the same direction as that preferred by the center suppressed responses, thus rendering these neurons unresponsive to wide-field motion. In the second set of complementary, interdigitated columns, neuronal receptive fields had reinforcing surrounds and responded optimally to wide-field motion. This functional organization could not be accounted for by systematic differences in binocular disparity. Within both column types, neurons whose receptive fields exhibited center-surround interactions were found less frequently in the input layers compared with the other layers. Additional tests were done on single units to examine the nature of the center-surround interactions. The direction tuning of the surround was broader than that of the center, and the preferred direction, with respect to that of the center, tended to be either in the same or opposite direction and only rarely in orthogonal directions. Surround motion at various velocities modulated the overall responsiveness to centrally placed moving stimuli, but it did not produce shifts in the peaks of the center's tuning curves for either direction or speed. In layers 3B and 5 of the local motion processing columns, a number of neurons responded only to local motion contrast but did so over a region of the visual field that was much larger than the optimal stimulus size. The central feature of this receptive field type was the generalization of surround antagonism over retinotopic space-a property similar to other "complex" receptive fields described previously. The columnar organization of different types of center-surround interactions may reflect the initial segregation of visual motion information into wide-field and local motion contrast systems that serve complementary functions in visual motion processing. Such segregation appears to occur at later stages of the macaque motion processing stream, in the medial superior temporal area (MST), and has also been described in invertebrate visual systems where it appears to be involved in the important function of distinguishing background motion from object motion.