Barthélemy Frédéric V, Vanzetta Ivo, Masson Guillaume S
Institut de Neurosciences Cognitives de la Méditerranée, Centre National de la Recherche Scientifique Unité Mixte de Recherche 6193, Aix-Marseille Université, Marseille, France.
J Neurophysiol. 2006 Jun;95(6):3712-26. doi: 10.1152/jn.00112.2006. Epub 2006 Mar 22.
Visual neurons integrate information over a finite part of the visual field with high selectivity. This classical receptive field is modulated by peripheral inputs that play a role in both neuronal response normalization and contextual modulations. However, the consequences of these properties for visuomotor transformations are yet incompletely understood. To explore those, we recorded short-latency ocular following responses in humans to large center-only and center-surround stimuli. We found that eye movements are triggered by a mechanism that integrates motion over a restricted portion of the visual field, the size of which depends on stimulus contrast and increases as a function of time after response onset. We also found evidence for a strong nonisodirectional center-surround organization, responsible for normalizing the central, driving input so that motor responses are set to their most linear contrast dynamics. Such response normalization is delayed about 20 ms relative to tracking onset, gradually builds up over time, and is partly tuned for surround orientation/direction. These results outline the spatiotemporal organization of a behavioral receptive field, which might reflect a linear integration among subpopulations of cortical visual motion detectors.
视觉神经元在视野的有限部分整合信息，具有高度选择性。这个经典感受野受到外周输入的调制，外周输入在神经元反应归一化和上下文调制中都发挥作用。然而，这些特性对视觉运动转换的影响尚未完全理解。为了探究这些影响，我们记录了人类对仅中心和中心-外周大刺激的短潜伏期眼球跟随反应。我们发现，眼球运动由一种机制触发，该机制在视野的受限部分整合运动，其大小取决于刺激对比度，并随反应开始后的时间增加。我们还发现了强烈的非等方向性中心-外周组织的证据，该组织负责归一化中央驱动输入，以便运动反应设置为其最线性的对比度动态。这种反应归一化相对于跟踪开始延迟约20毫秒，随时间逐渐增强，并且部分针对外周方向/方向进行调整。这些结果概述了行为感受野的时空组织，这可能反映了皮质视觉运动探测器亚群之间的线性整合。
