Human visual cortex is partitioned into different functional areas that, from lower to higher, become increasingly selective and responsive to complex feature dimensions. Here we use a Representational Similarity Analysis (RSA) of fMRI-BOLD signals to make quantitative comparisons across LGN and multiple visual areas of the low-level stimulus information encoded in the patterns of voxel responses. Our stimulus set was picked to target the four functionally distinct subcortical channels that input visual cortex from the LGN: two achromatic sinewave stimuli that favor the responses of the high-temporal magnocellular and high-spatial parvocellular pathways, respectively, and two chromatic stimuli isolating the L/M-cone opponent and S-cone opponent pathways, respectively. Each stimulus type had three spatial extents to sample both foveal and para-central visual field. With the RSA, we compare quantitatively the response specializations for individual stimuli and combinations of stimuli in each area and how these change across visual cortex. First, our results replicate the known response preferences for motion/flicker in the dorsal visual areas. In addition, we identify two distinct gradients along the ventral visual stream. In the early visual areas (V1-V3), the strongest differential representation is for the achromatic high spatial frequency stimuli, suitable for form vision, and a very weak differentiation of chromatic versus achromatic contrast. Emerging in ventral occipital areas (V4, VO1 and VO2), however, is an increasingly strong separation of the responses to chromatic versus achromatic contrast and a decline in the high spatial frequency representation. These gradients provide new insight into how visual information is transformed across the visual cortex.

中文翻译：

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fMRI 表征相似性分析揭示了人类视觉皮层对彩色和非彩色刺激对比度的分级偏好。

人类视觉皮层被划分为不同的功能区域，从低到高，对复杂特征维度的选择性和响应能力越来越强。在这里，我们使用 fMRI-BOLD 信号的表征相似性分析 (RSA) 对 LGN 和以体素响应模式编码的低级刺激信息的多个视觉区域进行定量比较。选择我们的刺激集以针对从 LGN 输入视觉皮层的四个功能不同的皮层下通道：两个消色差正弦波刺激，分别有利于高时间大细胞和高空间细小细胞通路的反应，以及两个色度刺激隔离L/M 锥对手和 S 锥对手通路，分别。每种刺激类型都有三个空间范围来采样中央凹和旁中央视野。使用 RSA，我们定量比较了每个区域中单个刺激和刺激组合的响应特化，以及这些在视觉皮层中的变化。首先，我们的结果复制了背侧视觉区域中运动/闪烁的已知响应偏好。此外，我们确定了沿着腹侧视觉流的两个不同的梯度。在早期视觉区域（V1-V3），最强的差异表征是消色差高空间频率刺激，适用于形式视觉，以及色差与消色差对比度的非常弱的区分。然而，出现在枕侧腹侧区域（V4、VO1 和 VO2），是对彩色与非彩色对比度的响应的越来越强烈的分离以及高空间频率表示的下降。这些梯度提供了对视觉信息如何在视觉皮层中转换的新见解。