Kilavik Bjørg Elisabeth, Kremers Jan
Department of Experimental Ophthalmology, University of Tübingen Eye Hospital, Tübingen, Germany.
Vis Neurosci. 2006 Mar-Apr;23(2):201-7. doi: 10.1017/S095252380623205X.
The dynamics of interactions between rod and L-cone driven signals were studied psychophysically in two deuteranopic observers. Flicker detection thresholds for different ratios of rod to L-cone modulation were measured at temporal frequencies between 1 and 15 Hz. A model, which assumes that rod and L-cone driven signals are vector added, can describe the threshold data adequately. We found that up to about 8-10 Hz temporal frequency, rod and L-cone signals interact additively, whereas at higher frequencies the interaction is subtractive. Rod and L-cone signal strengths depend similarly on temporal frequency and are maximal between 3 and 5 Hz. The phase difference between rod and L-cone signals increases linearly with temporal frequency, indicating that their responses have a delay difference of about 20 to 30 ms, consistent with involvement of the faster rod pathway. The data would suggest a nearly complete additivity of the rod and cone driven signals when using flashed stimuli. But, literature data showed only partial additivity of the two, suggesting that different postreceptoral mechanisms are involved in the two tasks.
在两名绿色盲观察者中，采用心理物理学方法研究了视杆细胞和L-视锥细胞驱动信号之间的相互作用动态。在1至15赫兹的时间频率下，测量了视杆细胞与L-视锥细胞不同调制比率下的闪烁检测阈值。一个假设视杆细胞和L-视锥细胞驱动信号进行矢量相加的模型，能够充分描述阈值数据。我们发现，在大约8至10赫兹的时间频率以下，视杆细胞和L-视锥细胞信号进行相加性相互作用，而在更高频率下，相互作用则是相减性的。视杆细胞和L-视锥细胞的信号强度对时间频率的依赖性相似，且在3至5赫兹之间达到最大值。视杆细胞和L-视锥细胞信号之间的相位差随时间频率呈线性增加，这表明它们的反应存在约20至30毫秒的延迟差异，这与更快的视杆细胞通路的参与情况一致。这些数据表明，在使用闪光刺激时，视杆细胞和视锥细胞驱动的信号几乎完全相加。但是，文献数据显示两者仅部分相加，这表明在这两项任务中涉及不同的感受器后机制。
