Purpose

To study the spatial retinal distribution of electroretinographic (ERG) responses that reflect signals in the L-/M-cone-opponent and luminance post-receptoral pathways.

Methods

ERG recordings to heterochromatic stimuli (sinusoidal counter-phase modulation of red and green LED light sources) were performed, while varying fractions of red and green modulation. Two temporal frequencies of the stimuli were employed: 12 Hz to record ERGs that reflect L-/M-cone-opponent signal and 36 Hz for recording ERG signals sensitive to stimulus luminance. Stimuli were about 20° in diameter and projected on various retinal locations: the fovea and four eccentricities (10°, 19°, 28° and 35°), each presented nasally, temporally, inferiorly and superiorly from the fovea.

Results

The 36 Hz stimuli elicited responses that strongly varied with red fraction and were minimal at iso-luminance. Moreover, response phases changed abruptly at the minimum by 180°. In contrast, the responses to the 12 Hz stimuli had amplitudes and phases that changed more gradually with red fraction. The 36 Hz response amplitudes were maximal close to the fovea and sharply decreased with increasing distance from the fovea. The responses to 12 Hz stimuli were more broadly distributed across the retina.

Conclusions

In the present study, it was found that retinal eccentricity and direction from the fovea have distinct effects on ERGs reflecting different post-receptoral mechanisms. The results are in accord with previous findings that ERGs to 12 Hz stimuli are predominantly determined by the red–green chromatic content of the stimuli, thus reflecting activation in the L-/M-cone-opponent pathway, while responses to 36 Hz stimuli manifest post-receptoral luminance-dependent activation. We found that the response in the cone-opponent pathway is broadly comparable across the retina; in comparison, response amplitude of the luminance pathway strongly depends on retinal stimulus position.

中文翻译：

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反射亮度和L-/M-锥体信号的ERGs的空间分布

目的

研究视网膜电图 (ERG) 反应的空间视网膜分布，这些反应反映了 L-/M-锥体-对手和亮度后受体通路中的信号。

方法

对异色刺激（红色和绿色 LED 光源的正弦反相调制）进行 ERG 记录，同时改变红色和绿色调制的分数。采用了两种刺激的时间频率：12 Hz 用于记录反映 L-/M-锥对手信号的 ERG，36 Hz 用于记录对刺激亮度敏感的 ERG 信号。刺激的直径约为 20°，并投射到不同的视网膜位置：中央凹和四个偏心（10°、19°、28° 和 35°），每个都从中央凹呈现在鼻部、颞部、下方和上方。

结果

36 Hz 刺激引起的响应随红色分数强烈变化，并且在等亮度下最小。此外，响应相位以 180° 的最小值突然变化。相比之下，对 12 Hz 刺激的响应的幅度和相位随着红色部分的变化而逐渐变化。36 Hz 响应幅度在靠近中央凹处最大，并随着与中央凹距离的增加而急剧下降。对 12 Hz 刺激的反应更广泛地分布在视网膜上。

结论

在本研究中，发现来自中央凹的视网膜离心率和方向对反映不同后接受机制的 ERG 有不同的影响。结果与先前的发现一致，即对 12 Hz 刺激的 ERG 主要由刺激的红绿色色含量决定，因此反映了 L-/M-cone-对手通路中的激活，而对 36 Hz 刺激的反应则明显接受后亮度依赖性激活。我们发现，锥体对抗通路中的反应在整个视网膜上具有广泛的可比性；相比之下，亮度通路的响应幅度很大程度上取决于视网膜刺激位置。