Givre S J, Arezzo J C, Schroeder C E
Department of Neuroscience, Rose F. Kennedy Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Vis Neurosci. 1995 Mar-Apr;12(2):229-39. doi: 10.1017/s0952523800007914.
Responses to full-field colored flashes (red, blue, and green) were compared with those to illuminance-matched white flashes in area V1, optic radiations, and the lateral geniculate nucleus of two alert macaques. Laminar profiles of visual evoked potentials (VEPs), current source density, and multiunit activity were obtained using multicontact electrodes capable of sampling from all layers of cortex or lateral geniculate nucleus, simultaneously. In striate cortex, stimulation with colored flash enhanced transmembrane current flow dramatically in both layer 4c and the supragranular laminae. Stimulation with red evoked the largest enhancement in every electrode penetration. The mean peak amplitudes of current sinks evoked by red were 203% and 537% of those evoked by white light in layer 4c and the supragranular laminae, respectively. Color effects in V1 were preceded by an initial epoch of wavelength-insensitive activity. In layer 4c, the red effect reached significance, on average, at 47 ms, or approximately 24 ms after the onset of transmembrane current flow. In the supragranular layers, the red effect reached significance, on average, at 55 ms, or approximately 14 ms after the onset of current flow. Recordings from optic radiations in the white matter below V1 and from lateral geniculate nucleus showed no significant difference in the responses to color and illuminance-matched white light. Enhancement of supragranular current flow with color stimulation increased the contribution of these laminae to the generation of the surface VEP. Comparison of the surface VEP wave forms evoked by white and color stimuli may, therefore, help to differentiate the responses of the granular and supragranular laminae.
在两只警觉猕猴的V1区、视辐射和外侧膝状核中，比较了对全视野彩色闪光（红色、蓝色和绿色）与照度匹配的白色闪光的反应。使用能够同时从皮质或外侧膝状核的所有层进行采样的多触点电极，获得了视觉诱发电位（VEP）、电流源密度和多单位活动的层状分布图。在纹状皮质中，彩色闪光刺激在4c层和颗粒上层中显著增强了跨膜电流流动。红色刺激在每个电极穿刺中引起的增强最大。红色诱发的电流汇的平均峰值幅度在4c层和颗粒上层中分别是白光诱发的203%和537%。V1区的颜色效应之前有一个对波长不敏感的活动初始阶段。在4c层，红色效应平均在47毫秒达到显著水平，即跨膜电流流动开始后约24毫秒。在颗粒上层，红色效应平均在55毫秒达到显著水平，即电流流动开始后约14毫秒。从V1下方白质中的视辐射和外侧膝状核的记录显示，对颜色和照度匹配的白光的反应没有显著差异。颜色刺激增强颗粒上层的电流流动增加了这些层对表面VEP产生的贡献。因此，比较白色和颜色刺激诱发的表面VEP波形可能有助于区分颗粒层和颗粒上层的反应。
