Selectivity and spatial distribution of signals from the receptive field surround in macaque V1 neurons
Selectivity and spatial distribution of signals from the receptive field surround in macaque V1 neurons
复制标题
DOI：
10.1152/jn.00693.2001
复制
发表时间：
2002-11-01
影响因子：
2.5
通讯作者：
Movshon, JA
中科院分区：
文献类型：
--
作者：
Cavanaugh, JR;Bair, W;Movshon, JA
V1神经元的反应性是由置于其经典感受野之外的刺激调节的。这种非经典的环绕环境提供了比最初想象的更大一部分视觉场景的输入，允许在视觉处理流的早期阶段整合信息。来自环绕的信号被报道为抑制性和促进性，选择性和非选择性。我们通过研究漂移正弦光栅之间的相互作用来测试来自环绕影响的特异性，这些光栅被谨慎地限制在保守定义的中心和环绕区域内。我们发现，当环绕光栅位于神经元的首选方向时，环绕效应总是被抑制的。当环绕光栅也向神经元偏好的方向移动时，抑制倾向于更强，而不是相反。当环绕体的取向与首选取向呈90度（正交）时，抑制较弱，有时会有明显的促进作用。因此，环绕信号的调谐倾向于与中心的调谐相匹配，尽管环绕的调谐有点宽。抑制的调节还取决于中心光栅的对比度，当中心光栅的对比度降低时，正交环绕刺激的抑制作用相对更强。我们还发现了环绕的调谐在一定程度上依赖于中心所使用的刺激的证据——当环绕光栅的参数与中心光栅的参数相匹配时，即使中心光栅本身不是最佳方向或方向，对于给定的中心刺激，抑制往往更强。我们还探索了环绕影响的空间分布，发现环绕区域的光栅斑块方向与最大抑制位置之间存在有序关系。当周围光栅平行于感觉野的首选方向时，感受野末端的抑制最强。当环绕光栅正交时，侧翼的抑制最强。我们得出结论，周围环境对经典感受野的反应有复杂的影响。我们认为这种复杂性的潜在机制可能涉及相对简单的中心和环绕机制之间的相互作用。
The responsiveness of neurons in V1 is modulated by stimuli placed outside their classical receptive fields. This nonclassical surround provides input from a larger portion of the visual scene than originally thought, permitting integration of information at early levels in the visual processing stream. Signals from the surround have been reported variously to be suppressive and facilitatory, selective and unselective. We tested the specificity of influences from the surround by studying the interactions between drifting sinusoidal gratings carefully confined to conservatively defined center and surround regions. We found that the surround influence was always suppressive when the surround grating was at the neuron's preferred orientation. Suppression tended to be stronger when the surround grating also moved in the neuron's preferred direction, rather than its opposite. When the orientation in the surround was 90degrees from the preferred orientation (orthogonal), suppression was weaker, and facilitation was sometimes evident. The tuning of surround signals therefore tended to match the tuning of the center, though the tuning of the surround was somewhat broader. The tuning of suppression also depended on the contrast of the center grating-when the center grating was reduced in contrast, orthogonal surround stimuli became relatively more suppressive. We also found evidence for the tuning of the surround being dependent to some degree on the stimulus used in the center-suppression was often stronger for a given center stimulus when the parameters of the surround grating matched the parameters of the center grating even when the center grating was not itself of the optimal direction or orientation. We also explored the spatial distribution of surround influence and found an orderly relationship between the orientation of grating patches presented to regions of the surround and the position of greatest suppression. When surround gratings were oriented parallel to the preferred orientation of the receptive field, suppression was strongest at the receptive field ends. When surround gratings were orthogonal, suppression was strongest on the flanks. We conclude that the surround has complex effects on responses from the classical receptive field. We suggest that the underlying mechanism of this complexity may involve interactions between relatively simple center and surround mechanisms.