Contrast adaptation and representation in human early visual cortex
Contrast adaptation and representation in human early visual cortex
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DOI：
10.1016/j.neuron.2005.07.016
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发表时间：
2005-08-18
期刊：
影响因子：
16.2
通讯作者：
Cheng, K
中科院分区：
文献类型：
--
作者：
Gardner, JL;Sun, P;Cheng, K
人类视觉系统可以区分图像对比度的变化，其范围比视觉皮质中对比度和反应之间静态关系的测量所表明的范围要大得多。这种差异可以解释，如果适应服务于重新中心周围的环境对比度的对比度响应函数，但对人类的实验尚未报告这样的效果。通过使用事件相关fMR 1和数据驱动的分析方法，我们发现V1，V2和V3中的对比度响应函数偏移到近似中心的适应对比度。此外，我们发现，与早期的区域不同，人类V4（hV4）对对比度的变化（无论是增量还是减量）有积极的反应，这表明hV4并不能忠实地代表对比度，而是对显着的变化有反应。这些研究结果表明，视觉系统折扣缓慢的无信息的变化与适应，但仍然非常敏感的变化，可能信号的重要事件在环境中。
The human visual system can distinguish variations in image contrast over a much larger range than measurements of the static relationship between contrast and response in visual cortex would suggest. This discrepancy may be explained if adaptation serves to recenter contrast response functions around the ambient contrast, yet experiments on humans have yet to report such an effect. By using event-related fMRl and a data-driven analysis approach, we found that contrast response functions in V1, V2, and V3 shift to approximately center on the adapting contrast. Furthermore, we discovered that, unlike earlier areas, human V4 (hV4) responds positively to contrast changes, whether increments or decrements, suggesting that hV4 does not faithfully represent contrast, but instead responds to salient changes. These findings suggest that the visual system discounts slow uninformative changes in contrast with adaptation, yet remains exquisitely sensitive to changes that may signal important events in the environment.