Crognale M A, Jacobs G H
Department of Psychology, University of California, Santa Barbara.
Vis Neurosci. 1991 Jun;6(6):593-606. doi: 10.1017/s0952523800002583.
Behavioral and electrophysiological methods were used to measure sensitivity to flickering lights in a dichromatic species, the California ground squirrel (Spermophilus beecheyi). Discrimination tests were used to determine spectral sensitivity at stimulus frequencies from 5-50 Hz and increment threshold spectral sensitivity. The contributions of retinal mechanisms to these capacities were assessed by recording the responses of optic nerve fibers to temporally modulated monochromatic lights. In the ground squirrel, as in the human, the shape of the spectral-sensitivity function depends on the temporal frequency of the stimulus. Results from single-unit recording show that all of the classes of optic nerve fibers in the ground squirrel are highly phase-locked to the stimulus for modulation rates as high as 50 Hz. Neither the responses of photoreceptors nor any class of optic nerve fiber can singly account for the behavioral results. The electrophysiological results are also counter to models which propose that temporally dependent changes in the spectral sensitivity of spectrally opponent fibers account for the behavior. The temporal resolution of the optic nerve fibers exceeds that of the behaving animal suggesting that retinal mechanisms do not limit behavioral temporal resolution.
行为学和电生理学方法被用于测量二色性物种——加利福尼亚地松鼠（Spermophilus beecheyi）对闪烁光的敏感度。辨别测试用于确定在5 - 50赫兹刺激频率下的光谱敏感度以及增量阈值光谱敏感度。通过记录视神经纤维对时间调制单色光的反应，评估视网膜机制对这些能力的贡献。与人类一样，在加利福尼亚地松鼠中，光谱敏感度函数的形状取决于刺激的时间频率。单单位记录结果表明，加利福尼亚地松鼠中所有类别的视神经纤维对于高达50赫兹的调制率都能高度锁相于刺激。光感受器的反应以及任何一类视神经纤维都无法单独解释行为学结果。电生理学结果也与那些认为光谱拮抗纤维的光谱敏感度随时间变化来解释该行为的模型相悖。视神经纤维的时间分辨率超过了行为动物的时间分辨率，这表明视网膜机制并不限制行为的时间分辨率。
