Regan D
Vision Res. 1983;23(12):1401-7. doi: 10.1016/0042-6989(83)90151-7.
Two visually evoked brain responses were elicited simultaneously by stimulating the eye with two superimposed sinewave grating patterns that were temporally modulated at slightly different rates. The VEP to one grating was comparatively little affected by the presence of the other grating when the two spatial frequencies were very different, but mutual attenuation grew stronger and stronger as the spatial frequencies of the two gratings were progressively brought together. The attenuation rose to a sharp maximum when the two spatial frequencies were equal. This held at each of the five spatial frequencies tested. This finding can be explained if the spatially-selective mechanisms responsible for grating VEPs contain multiple subunits of narrower spatial frequency bandwidth. The two-grating technique was also used to search for evidence of multiple subunits that are most sensitive at the same spatial frequency, but are tuned to different temporal frequencies. Findings were quite different for temporal and for spatial tuning. Attenuation of one grating VEP was greatest when the temporal frequency of the other grating fell within a broad frequency range of about 3-30 reversals sec-1: maximum attenuation could occur when the gratings had quite different temporal frequencies. This finding denies that for every given temporal frequency there is a subunit maximally sensitive to that frequency.
通过用两个叠加的正弦波光栅图案刺激眼睛，同时诱发了两种视觉诱发的脑反应，这两个图案在时间上以略有不同的速率进行调制。当两个空间频率非常不同时，对一个光栅的视觉诱发电位（VEP）受另一个光栅存在的影响相对较小，但随着两个光栅的空间频率逐渐靠近，相互衰减变得越来越强。当两个空间频率相等时，衰减急剧上升到最大值。在测试的五个空间频率中的每一个频率下都是如此。如果负责光栅VEP的空间选择性机制包含多个空间频率带宽较窄的亚单位，那么这一发现就可以得到解释。双光栅技术还被用于寻找多个亚单位的证据，这些亚单位在相同空间频率下最敏感，但被调谐到不同的时间频率。时间调谐和空间调谐的结果截然不同。当另一个光栅的时间频率落在大约3 - 30次反转/秒的宽频率范围内时，一个光栅VEP的衰减最大：当光栅具有相当不同的时间频率时，可能会出现最大衰减。这一发现否认了对于每一个给定的时间频率都存在一个对该频率最敏感的亚单位。
