Masking reduces orientation selectivity in rat visual cortex
Masking reduces orientation selectivity in rat visual cortex
复制标题
DOI：
10.1152/jn.00366.2016
复制
发表时间：
2016-11-01
影响因子：
2.5
通讯作者：
Price, Nicholas S. C.
中科院分区：
文献类型：
--
作者：
Alwis, Dasuni S.;Richards, Katrina L.;Price, Nicholas S. C.
在视觉掩蔽中，对目标刺激的感知会受到前面（向前）或后面（向后）掩蔽刺激的损害。错觉之所以有趣，是因为它允许物理刺激、其神经元表征和其感知的解耦。为了了解掩蔽的神经元相关性，我们研究了掩蔽如何影响麻醉大鼠（n = 37）初级视皮层（V1）中定向靶刺激的神经元反应。目标刺激是具有12个方向的圆形光栅;掩模刺激是作为所有可能的目标方向的二进制化总和而创建的格子。在空间上，掩模呈现为重叠或围绕目标。在时间上，目标和面具提出了33毫秒，但刺激起始时间（SOA）的相对外观是不同的。这是第一次，我们研究空间重叠和中心环绕掩蔽如何影响V1中的方向可辨别性（而不是可见性）。无论刺激的空间或时间安排，最短的SOA发生在放电率和方向选择性的最大减少。有趣的是，分别进行分析的瞬态和持续的目标响应组件显示，方向选择性的变化并不总是一致的发射率的变化。考虑到观察到的方向选择性，即使当目标和掩模不空间重叠的近瞬时减少，我们建议，单调的视觉掩蔽的神经整合和侧抑制的组合来解释。
In visual masking the perception of a target stimulus is impaired by a preceding (forward) or succeeding (backward) mask stimulus. The illusion is of interest because it allows uncoupling of the physical stimulus, its neuronal representation, and its perception. To understand the neuronal correlates of masking, we examined how masks affected the neuronal responses to oriented target stimuli in the primary visual cortex (V1) of anesthetized rats (n = 37). Target stimuli were circular gratings with 12 orientations; mask stimuli were plaids created as a binarized sum of all possible target orientations. Spatially, masks were presented either overlapping or surrounding the target. Temporally, targets and masks were presented for 33 ms, but the stimulus onset asynchrony (SOA) of their relative appearance was varied. For the first time, we examine how spatially overlapping and center-surround masking affect orientation discriminability (rather than visibility) in V1. Regardless of the spatial or temporal arrangement of stimuli, the greatest reductions in firing rate and orientation selectivity occurred for the shortest SOAs. Interestingly, analyses conducted separately for transient and sustained target response components showed that changes in orientation selectivity do not always coincide with changes in firing rate. Given the near-instantaneous reductions observed in orientation selectivity even when target and mask do not spatially overlap, we suggest that monotonic visual masking is explained by a combination of neural integration and lateral inhibition.