Troy J B, Enroth-Cugell C
Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208.
Exp Brain Res. 1993;93(3):383-90. doi: 10.1007/BF00229354.
It has been suggested for a number of years that ganglion cells inform the rest of the brain about contrast in the retinal image. The purpose of the work undertaken here was to demonstrate this fact explicitly. Extracellular recordings were made from X- and Y-cell axons of the optic tracts of anesthetized cats. Responses of these cells to gratings that were near optimal in spatial and temporal frequency were measured for a range of contrasts. For each cell, similar measurements were made at a number of light levels, spanning the photopic to high scotopic (inclusive) ranges. A monotonic relationship between response and contrast was found at all light levels studied, and the same relationship was retained to a good approximation across all light levels. A similar result was also found when nonoptimal spatial frequencies were used as stimuli. These results indicate strongly that X and Y cells inform the cat's brain about contrast in the retinal image. It was also observed that the mean discharge rate of X and Y cells did not change with light level, indicating that no information is relayed to the brain by these cells on the mean light level.
多年来一直有人提出，神经节细胞会将视网膜图像中的对比度信息传递给大脑的其他部分。此处开展这项工作的目的就是要明确地证明这一事实。对麻醉猫的视束中的X细胞和Y细胞轴突进行了细胞外记录。针对一系列对比度，测量了这些细胞对空间和时间频率接近最佳值的光栅的反应。对于每个细胞，在多个光照水平下进行了类似的测量，涵盖了明视觉到高暗视觉（包括两端）范围。在所研究的所有光照水平下，都发现反应与对比度之间存在单调关系，并且在所有光照水平下这种关系都能很好地保持近似。当使用非最佳空间频率作为刺激时，也发现了类似的结果。这些结果有力地表明，X细胞和Y细胞会将视网膜图像中的对比度信息传递给猫的大脑。还观察到，X细胞和Y细胞的平均放电率不会随光照水平而变化，这表明这些细胞不会将平均光照水平的信息传递给大脑。
