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首页> 外文期刊>The European Journal of Neuroscience >BOLD human responses to chromatic spatial features
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BOLD human responses to chromatic spatial features

机译：人类对色彩空间特征的大胆反应

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Animal physiological and human psychophysical studies suggest that an early step in visual processing involves the detection and identification of features such as lines and edges, by neural mechanisms with even- and odd-symmetric receptive fields. Functional imaging studies also demonstrate mechanisms with even- and odd-receptive fields in early visual areas, in response to luminance-modulated stimuli. In this study we measured fMRI BOLD responses to 2-D stimuli composed of only even or only odd symmetric features, and to an amplitude-matched random noise control, modulated in red-green equiluminant colour contrast. All these stimuli had identical power but different phase spectra, either highly congruent (even or odd symmetry stimuli) or random (noise). At equiluminance, V1 BOLD activity showed no preference between congruent- and random-phase stimuli, as well as no preference between even and odd symmetric stimuli. Areas higher in the visual hierarchy, both along the dorsal pathway (caudal part of the intraparietal sulcus, dorsal LO and V3A) and the ventral pathway (V4), responded preferentially to odd symmetry over even symmetry stimuli, and to congruent over random phase stimuli. Interestingly, V1 showed an equal increase in BOLD activity at each alternation between stimuli of different symmetry, suggesting the existence of specialised mechanisms for the detection of edges and lines such as even- and odd-chromatic receptive fields. Overall the results indicate a high selectivity of colour-selective neurons to spatial phase along both the dorsal and the ventral pathways in humans.
机译：动物生理学和人类心理生理学研究表明，视觉处理的早期步骤涉及通过具有偶数和奇数对称接收场的神经机制来检测和识别线条和边缘等特征。功能成像研究还表明，响应于亮度调制的刺激，早期视觉区域具有偶数和奇数感受野的机制。在这项研究中，我们测量了fMRI BOLD对仅由偶数或仅奇数个对称特征组成的2-D刺激以及对振幅匹配的随机噪声控制（以红绿色等亮度色差进行调制）的响应。所有这些刺激具有相同的功效，但相位谱却不同，或者是高度一致的（偶数或奇数对称刺激）或随机的（噪声）。在平衡时，V1 BOLD活性在全相和随机相刺激之间没有优先选择，在偶数和奇数对称刺激之间也没有显示优先选择。沿背侧途径（顶内沟的尾部，背侧LO和V3A）和腹侧途径（V4）的视觉层次较高的区域，对奇数对称性比偶数对称性刺激优先，而对随机相点同等式优先。 。有趣的是，V1在不同对称性的刺激之间的每次交替中都显示出BOLD活性的均等增加，这表明存在用于检测边缘和线条（例如偶数和奇数色接收场）的专门机制。总体而言，结果表明颜色选择性神经元对人的背侧和腹侧路径对空间相的高度选择性。

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