Maehara Goro, Huang Pi-Chun, Hess Robert F
McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montreal, Quebec, Canada.
Vision Res. 2009 Jul;49(14):1838-47. doi: 10.1016/j.visres.2009.04.020. Epub 2009 May 3.
We measured contrast thresholds for Gabor targets in the presence of maskers which had higher or lower spatial frequencies than the targets. A high-pass fractal masker elevated target contrast thresholds at low and intermediate pedestal contrasts in both monocular and dichoptic modes of presentation, suggesting that the masking occurs after a monocular processing stage. Moreover we found that a high-pass checkerboard masker elevated thresholds at the low and intermediate pedestal contrasts and that most of this threshold elevation disappeared when the phase of the masker's spatial components were scrambled. This masking was effective only in the dichoptic presentation, not in the monocular presentation. These results indicate that phase alignment of the high spatial frequency components plays a crucial role for interocular suppression. We speculate that phase alignments signal the existence of a luminance contour in the monocular image and that this signal suppresses processing of information in the other eye when there is no corresponding signal in that eye.
我们测量了在存在空间频率高于或低于目标的掩蔽物的情况下，Gabor目标的对比度阈值。高通分形掩蔽物在单眼和双眼呈现模式下，在低和中等背景对比度时都会提高目标对比度阈值，这表明掩蔽发生在单眼处理阶段之后。此外，我们发现高通棋盘格掩蔽物在低和中等背景对比度时会提高阈值，并且当掩蔽物空间成分的相位被打乱时，大部分这种阈值升高现象会消失。这种掩蔽仅在双眼呈现中有效，在单眼呈现中无效。这些结果表明，高空间频率成分的相位对齐对双眼抑制起着关键作用。我们推测，相位对齐表明单眼图像中存在亮度轮廓，并且当另一只眼睛中没有相应信号时，该信号会抑制另一只眼睛中信息的处理。
