Pasupathy Anitha, Connor Charles E
Center for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Nat Neurosci. 2002 Dec;5(12):1332-8. doi: 10.1038/nn972.
Shape is represented in the visual system by patterns of activity across populations of neurons. We studied the population code for shape in area V4 of macaque monkeys, which is part of the ventral (object-related) pathway in primate visual cortex. We have previously found that many macaque V4 neurons are tuned for the curvature and object-centered position of boundary fragments (such as 'concavity on the right'). Here we tested the hypothesis that populations of such cells represent complete shapes as aggregates of boundary fragments. To estimate the population representation of a given shape, we scaled each cell's tuning peak by its response to that shape, summed across cells and smoothed. The resulting population response surface contained 3-8 peaks that represented major boundary features and could be used to reconstruct (approximately) the original shape. This exemplifies how a multi-peaked neural population response can represent a complex stimulus in terms of its constituent elements.
形状在视觉系统中由神经元群体的活动模式来表征。我们研究了猕猴V4区中形状的群体编码，该区是灵长类视觉皮层腹侧（与物体相关）通路的一部分。我们之前发现，许多猕猴V4神经元对边界片段的曲率和以物体为中心的位置进行了调谐（例如“右侧凹陷”）。在这里，我们测试了这样一个假设，即这些细胞群体将完整形状表征为边界片段的集合。为了估计给定形状的群体表征，我们通过每个细胞对该形状的反应来缩放其调谐峰值，对细胞进行求和并平滑处理。由此产生的群体反应表面包含3 - 8个峰值，这些峰值代表主要边界特征，可用于（近似地）重建原始形状。这例证了多峰神经群体反应如何能够根据其组成元素来表征复杂刺激。
