Facilitation of contrast detection by cross-oriented surround stimuli and its psychophysical mechanisms.
Facilitation of contrast detection by cross-oriented surround stimuli and its psychophysical mechanisms.
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DOI：
10.1167/2.3.4
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发表时间：
2002-04
影响因子：
1.8
通讯作者：
Cong Yu;S. Klein;D. Levi
中科院分区：
文献类型：
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作者：
Cong Yu;S. Klein;D. Levi
神经生理学和心理物理学证据表明，交叉方向（与经典感受野的首选方向正交）的神经元环绕调制在中等水平的视觉任务中起关键作用，如纹理分离和知觉弹出。缺少的是在低水平视觉的空间滤波水平上交叉环绕调制的心理物理描述。此外，关于交叉环绕调制如何在神经元水平上表达的神经生理学证据一直不一致。在这里，我们报告了交叉环绕刺激（与目标取向正交）对对比检测的心理物理促进的证据，这可能为交叉环绕调制的神经生理学和心理物理学提供见解。我们发现，交叉环绕促进是一种环境-对比度依赖效应，主要在低环绕对比度下表现出来，并且狭窄地调谐到空间频率，广泛地调谐到方向。为了了解交叉环绕促进是由于低水平的信噪增强处理还是由于更高层次决策阶段的不确定性减少，我们(1)研究了具有等效噪声协议的交叉环绕促进，(2)估计了心理测量函数斜率和不确定性参数M的变化，以及(3)测量了TvC函数的交叉处的交叉环绕效应。越来越多的证据表明，交叉环绕对对比度检测的促进主要是低水平信噪比增强的结果，受不确定性变化的影响很小。
Neurophysiological and psychophysical evidence indicates that neuronal surround modulation at cross-orientation (orthogonal to the preferred orientation of the classical receptive field) plays a key role in intermediate-level visual tasks, such as textural segregation and perceptual pop-out. What is missing is a psychophysical description of cross surround modulation at the spatial filter level in low-level vision. Moreover, neurophysiological evidence for how cross surround modulation is expressed at the neuronal level has been inconsistent. Here we report evidence for psychophysical facilitation of contrast detection by cross surround stimuli (orthogonal to the target orientation) that may provide insights into both the neurophysiology and psychophysics of cross surround modulation. We found that cross surround facilitation is a surround-contrast dependent effect mainly evident at low surround contrasts, and is narrowly tuned to spatial frequency and broadly tuned to orientation. To understand whether cross surround facilitation results from low-level processing of signal-to-noise enhancement or is due to uncertainty reduction at a higher-level decision stage, we (1) studied cross surround facilitation with an equivalent noise protocol, (2) estimated the changes in the slope of the psychometric function and the uncertainty parameter, M, and (3) measured cross surround effects at the dipper of the TvC function. The converging evidence suggests that cross surround facilitation of contrast detection is mainly a result of low-level signal-to-noise enhancement, and is little affected by uncertainty change.