Doheny Retina Institute, Doheny Eye Institute, 1450 San Pablo St., Los Angeles, CA 90033, United States.
Neurosci Lett. 2010 Jul 26;479(2):92-6. doi: 10.1016/j.neulet.2010.05.031. Epub 2010 May 19.
Optokinetic testing is a non-invasive technique, widely used for visual functional evaluation in rodents. The modulatory influence of optokinetic stimulus parameters such as contrast level and grating speed on head-tracking response in normal and retinal degenerate (RD) mice (rd10) and rats (S334ter-line-3) was evaluated using a computer-based testing apparatus. In normal (non-RD) mice and rats, specific stripe width and grating speed was found to evoke maximum optokinetic head-tracking response. In line-3 RD rats, the contrast sensitivity loss was slow and remained close to the baseline (normal control) level until very late in the disease, whereas, in rd10 mice the progression of the contrast sensitivity loss was more rapid. Observed differences between rd10 mice and line-3 RD rats in the progression of contrast sensitivity loss may not be directly related to the degree of photoreceptor loss. In young RD mice, the modulatory influence of stimulus parameters on optokinetic head-tracking response was similar to normal control animals. During later stages, slower grating speed was required to evoke the maximum optokinetic response. Grating speed had lesser apparent influence on the response properties of line-3 RD rats. Discrepancies between the two RD models in the modulatory influence of optokinetic stimulus parameters can be the manifestation of fundamental species differences and/or differences in the degeneration pattern. This study highlights the importance of careful selection of appropriate stimulus parameters for testing optokinetic head-tracking response in RD animals.
视动测试是一种非侵入性技术，广泛应用于啮齿动物的视觉功能评估。使用基于计算机的测试设备评估了视动刺激参数（如对比度水平和光栅速度）对正常和视网膜变性（RD）小鼠（rd10）和大鼠（S334ter-line-3）的头部跟踪反应的调制影响。在正常（非 RD）小鼠和大鼠中，发现特定的条纹宽度和光栅速度会引起最大的视动头部跟踪反应。在 line-3 RD 大鼠中，对比度敏感度损失缓慢，直到疾病晚期仍接近基线（正常对照）水平，而在 rd10 小鼠中，对比度敏感度损失的进展更快。在对比度敏感度损失的进展方面，rd10 小鼠和 line-3 RD 大鼠之间观察到的差异可能与光感受器损失的程度没有直接关系。在年轻的 RD 小鼠中，刺激参数对视动头部跟踪反应的调制影响与正常对照动物相似。在后期阶段，需要较慢的光栅速度才能引起最大的视动反应。光栅速度对视动反应特性对 line-3 RD 大鼠的影响较小。两种 RD 模型对视动刺激参数的调制影响之间的差异可能是物种差异和/或变性模式差异的表现。这项研究强调了在 RD 动物中测试视动头部跟踪反应时仔细选择适当刺激参数的重要性。
