von der Heydt Rüdiger
The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore MD, USA.
Front Psychol. 2015 Nov 3;6:1695. doi: 10.3389/fpsyg.2015.01695. eCollection 2015.
A long history of studies of perception has shown that the visual system organizes the incoming information early on, interpreting the 2D image in terms of a 3D world and producing a structure that provides perceptual continuity and enables object-based attention. Recordings from monkey visual cortex show that many neurons, especially in area V2, are selective for border ownership. These neurons are edge selective and have ordinary classical receptive fields (CRF), but in addition their responses are modulated (enhanced or suppressed) depending on the location of a 'figure' relative to the edge in their receptive field. Each neuron has a fixed preference for location on one side or the other. This selectivity is derived from the image context far beyond the CRF. This paper reviews evidence indicating that border ownership selectivity reflects the formation of early object representations ('proto-objects'). The evidence includes experiments showing (1) reversal of border ownership signals with change of perceived object structure, (2) border ownership specific enhancement of responses in object-based selective attention, (3) persistence of border ownership signals in accordance with continuity of object perception, and (4) remapping of border ownership signals across saccades and object movements. Findings 1 and 2 can be explained by hypothetical grouping circuits that sum contour feature signals in search of objectness, and, via recurrent projections, enhance the corresponding low-level feature signals. Findings 3 and 4 might be explained by assuming that the activity of grouping circuits persists and can be remapped. Grouping, persistence, and remapping are fundamental operations of vision. Finding these operations manifest in low-level visual areas challenges traditional views of visual processing. New computational models need to be developed for a comprehensive understanding of the function of the visual cortex.
长期以来，感知研究表明，视觉系统会在早期对传入信息进行组织，根据三维世界来解释二维图像，并生成一种能提供感知连续性并支持基于物体的注意力的结构。对猴子视觉皮层的记录显示，许多神经元，尤其是V2区的神经元，对边界所有权具有选择性。这些神经元对边缘具有选择性，并且具有普通的经典感受野（CRF），但除此之外，它们的反应会根据“图形”相对于其感受野中边缘的位置而受到调制（增强或抑制）。每个神经元对一侧或另一侧的位置都有固定的偏好。这种选择性源自远超出CRF的图像背景。本文综述了相关证据，表明边界所有权选择性反映了早期物体表征（“原型物体”）的形成。证据包括实验表明：（1）随着感知物体结构的变化，边界所有权信号会发生反转；（2）在基于物体的选择性注意力中，边界所有权会特异性增强反应；（3）边界所有权信号会根据物体感知的连续性而持续存在；（4）边界所有权信号会在扫视和物体运动过程中进行重新映射。发现1和2可以通过假设的分组回路来解释，这些回路会对轮廓特征信号进行求和以寻找物体特征，并通过循环投射增强相应的低级特征信号。发现3和4可能通过假设分组回路的活动持续存在并可以重新映射来解释。分组、持续性和重新映射是视觉的基本操作。在低级视觉区域发现这些操作挑战了传统的视觉处理观点。需要开发新的计算模型，以便全面理解视觉皮层的功能。
