Sestokas A K, Lehmkuhle S
Vision Res. 1986;26(7):1041-54. doi: 10.1016/0042-6989(86)90038-6.
Visual response latencies and rise times of X- and Y-cells in the dorsal lateral geniculate nucleus (dLGN) of anaesthetized, paralyzed cats were measured during repeated stimulation with sinusoidal grating patterns. Measurements were restricted to individual stimulus trials on which the instantaneous discharge rate exceeded a criterion amplitude defined in terms of the baseline activity of each cell. The latencies of response onsets and response peaks were systematically related to the spatial frequency and contrast of the grating stimuli. Response latencies of Y-cells were shortest for gratings of low spatial frequency (0.17 c/deg) and increased monotonically with increases in spatial frequency. Response latencies of X-cells were shortest for gratings of intermediate spatial frequency (0.75 c/deg) and longer for lower and higher spatial frequencies. Latencies decreased monotonically with increases in stimulus contrast from 5 to 40% for both X- and Y-cells. In general, short-latency responses were less variable than long-latency responses. This was true for absolute as well as relative measures of variability. The mean onset and peak latencies of Y-cell responses were 10-15 msec shorter than the corresponding latencies of X-cell responses to stimuli of optimal spatial frequency and contrast. The rise times (latency of response peak minus latency of response onset) of Y-cell responses were consistently shorter than those of X-cells in spite of the higher peak responses of Y-cells. The results of this study are consistent with the idea that low spatial frequency information is passed through the lateral geniculate nucleus more quickly than is high spatial frequency information. These data provide support for models of visual processing wherein a coarse, global analysis of the visual scene by Y-cells precedes a finer, local analysis by X-cells.
在对麻醉、麻痹的猫的背外侧膝状核（dLGN）中的X细胞和Y细胞进行正弦光栅图案重复刺激期间，测量了视觉反应潜伏期和上升时间。测量仅限于单个刺激试验，在这些试验中，瞬时放电率超过了根据每个细胞的基线活动定义的标准幅度。反应起始和反应峰值的潜伏期与光栅刺激的空间频率和对比度系统相关。对于低空间频率（0.17周/度）的光栅，Y细胞的反应潜伏期最短，并且随着空间频率的增加而单调增加。对于中等空间频率（0.75周/度）的光栅，X细胞的反应潜伏期最短，而对于较低和较高空间频率则更长。对于X细胞和Y细胞，潜伏期随着刺激对比度从5%增加到40%而单调减少。一般来说，短潜伏期反应比长潜伏期反应的变异性小。这在变异性的绝对和相对测量中都是如此。Y细胞反应的平均起始和峰值潜伏期比X细胞对最佳空间频率和对比度刺激的相应潜伏期短10 - 15毫秒。尽管Y细胞的峰值反应较高，但其反应上升时间（反应峰值潜伏期减去反应起始潜伏期）始终比X细胞短。本研究结果与低空间频率信息比高空间频率信息更快地通过外侧膝状核的观点一致。这些数据为视觉处理模型提供了支持，其中Y细胞对视觉场景进行粗略的全局分析先于X细胞进行更精细的局部分析。
