Kuang Shenbing, Shi Jinfu, Wang Yang, Zhang Tao
State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.
Psych J. 2017 Jun;6(2):141-152. doi: 10.1002/pchj.165. Epub 2017 May 17.
As we move forward in the environment, we experience a radial expansion of the retinal image, wherein the center corresponds to the instantaneous direction of self-motion. Humans can precisely perceive their heading direction even when the retinal motion is distorted by gaze shifts due to eye/body rotations. Previous studies have suggested that both retinal and extra-retinal strategies can compensate for the retinal image distortion. However, the relative contributions of each strategy remain unclear. To address this issue, we devised a two-alternative-headings discrimination task, in which participants had either real or simulated pursuit eye movements. The two conditions had the same retinal input but either with or without extra-retinal eye movement signals. Thus, the behavioral difference between conditions served as a metric of extra-retinal contribution. We systematically and independently manipulated pursuit speed, heading speed, and the reliability of retinal signals. We found that the levels of extra-retinal contributions increased with increasing pursuit speed (stronger extra-retinal signal), and with decreasing heading speed (weaker retinal signal). In addition, extra-retinal contributions also increased as we corrupted retinal signals with noise. Our results revealed that the relative magnitude of retinal and extra-retinal contributions was not fixed but rather flexibly adjusted to each specific task condition. This task-dependent, flexible integration appears to take the form of a reliability-based weighting scheme that maximizes heading performance.
当我们在环境中移动时，我们会体验到视网膜图像的径向扩展，其中中心对应于自身运动的瞬时方向。即使视网膜运动因眼睛/身体旋转引起的注视转移而扭曲，人类也能精确感知其前进方向。先前的研究表明，视网膜和视网膜外策略都可以补偿视网膜图像失真。然而，每种策略的相对贡献仍不清楚。为了解决这个问题，我们设计了一个二选一的前进方向辨别任务，其中参与者进行真实或模拟的追踪眼球运动。这两种情况具有相同的视网膜输入，但分别有或没有视网膜外眼球运动信号。因此，两种情况之间的行为差异作为视网膜外贡献的一个衡量指标。我们系统地、独立地操纵追踪速度、前进速度和视网膜信号的可靠性。我们发现，视网膜外贡献的水平随着追踪速度的增加（更强的视网膜外信号）和前进速度的降低（较弱的视网膜信号）而增加。此外，当我们用噪声破坏视网膜信号时，视网膜外贡献也会增加。我们的结果表明，视网膜和视网膜外贡献的相对大小不是固定的，而是根据每个特定任务条件灵活调整的。这种依赖任务的灵活整合似乎采取了一种基于可靠性的加权方案的形式，以最大化前进方向的表现。
