Fries P, Schröder J H, Singer W, Engel A K
Max-Planck-Institute for Brain Research, Deutschordenstr. 46, 60528, Frankfurt, Germany.
Vision Res. 2001 Mar;41(6):771-83. doi: 10.1016/s0042-6989(00)00299-6.
Presenting the two eyes with incongruent stimuli leads to the phenomenon of interocular rivalry. At any given time, one of the stimuli is perceptually suppressed in order to avoid double vision. In squinting subjects, rivalry occurs permanently also for congruent stimuli because of developmental rearrangement of cortical circuitry. In this study, we have investigated the dynamics and stimulus dependence of rivalry in six esotropic, four exotropic and three non-strabismic cats. As an indicator for perception, we used optokinetic nystagmus that was induced by moving gratings. The esotropic cats were tested for their visual acuity by means of a jumping stand procedure. The results show that one eye can dominate perception even if both eyes have equal visual acuity and are presented with stimuli of equal contrast. Strong eye dominance asymmetry was found in all but one of the tested cats. Notably, all three of the normal cats showed a clear asymmetry in perceptual selection. Measurements with varying contrast and velocity of the stimuli revealed that the influence of these parameters on perceptual selection was independent of the presence of strabismus. In all cats, the time during which a given eye dominated perception increased with the contrast and decreases with the velocity of the stimulus presented to this eye.
给两只眼睛呈现不一致的刺激会导致双眼竞争现象。在任何给定时间，为了避免复视，其中一个刺激会在感知上被抑制。在斜视患者中，由于皮质神经回路的发育重排，对于一致的刺激也会永久发生竞争。在本研究中，我们调查了六只内斜视猫、四只外斜视猫和三只非斜视猫的竞争动态和刺激依赖性。作为感知的指标，我们使用了由移动光栅诱发的视动性眼球震颤。通过跳跃台程序对内斜视猫的视力进行了测试。结果表明，即使两只眼睛具有相同的视力并呈现相同对比度的刺激，一只眼睛也可以主导感知。在除一只受试猫之外的所有猫中都发现了强烈的眼优势不对称。值得注意的是，所有三只正常猫在感知选择上都表现出明显的不对称。对不同对比度和刺激速度的测量表明，这些参数对感知选择的影响与斜视的存在无关。在所有猫中，给定眼睛主导感知的时间随着呈现给该眼睛的刺激的对比度增加而增加，随着刺激速度降低而减少。
