Kimmel Daniel L, Mammo Dagem, Newsome William T
Department of Neurobiology, Howard Hughes Medical Institute, Stanford University Stanford, CA, USA.
Front Behav Neurosci. 2012 Aug 14;6:49. doi: 10.3389/fnbeh.2012.00049. eCollection 2012.
From human perception to primate neurophysiology, monitoring eye position is critical to the study of vision, attention, oculomotor control, and behavior. Two principal techniques for the precise measurement of eye position-the long-standing sclera-embedded search coil and more recent optical tracking techniques-are in use in various laboratories, but no published study compares the performance of the two methods simultaneously in the same primates. Here we compare two popular systems-a sclera-embedded search coil from C-N-C Engineering and the EyeLink 1000 optical system from SR Research-by recording simultaneously from the same eye in the macaque monkey while the animal performed a simple oculomotor task. We found broad agreement between the two systems, particularly in positional accuracy during fixation, measurement of saccade amplitude, detection of fixational saccades, and sensitivity to subtle changes in eye position from trial to trial. Nonetheless, certain discrepancies persist, particularly elevated saccade peak velocities, post-saccadic ringing, influence of luminance change on reported position, and greater sample-to-sample variation in the optical system. Our study shows that optical performance now rivals that of the search coil, rendering optical systems appropriate for many if not most applications. This finding is consequential, especially for animal subjects, because the optical systems do not require invasive surgery for implantation and repair of search coils around the eye. Our data also allow laboratories using the optical system in human subjects to assess the strengths and limitations of the technique for their own applications.
从人类感知到灵长类动物神经生理学，监测眼睛位置对于视觉、注意力、眼球运动控制和行为的研究至关重要。两种用于精确测量眼睛位置的主要技术——长期使用的巩膜嵌入搜索线圈和较新的光学跟踪技术——在各个实验室中都有应用，但尚无已发表的研究在同一灵长类动物中同时比较这两种方法的性能。在此，我们通过在猕猴执行简单眼球运动任务时同时记录同一只眼睛，比较了两种常用系统——C-N-C工程公司的巩膜嵌入搜索线圈和SR研究公司的EyeLink 1000光学系统。我们发现这两种系统之间具有广泛的一致性，特别是在注视期间的位置准确性、扫视幅度的测量、注视性扫视的检测以及每次试验中眼睛位置细微变化的敏感性方面。尽管如此，某些差异仍然存在，特别是扫视峰值速度升高、扫视后振铃、亮度变化对报告位置的影响以及光学系统中样本间的较大变化。我们的研究表明，光学性能现在可与搜索线圈相媲美，使光学系统适用于许多（如果不是大多数）应用。这一发现具有重要意义，特别是对于动物受试者，因为光学系统不需要进行侵入性手术来植入和修复眼睛周围的搜索线圈。我们的数据还使在人类受试者中使用光学系统的实验室能够评估该技术在其自身应用中的优势和局限性。
