Investigation of the human visual system by phychophysical and fMRI experiments

本研究旨在通过心理物理和功能磁共振实验来研究人类的视觉系统。在心理物理实验中，我们使用了通过观看闪避型虚拟现实系统(CAVE)呈现的全场运动而引发的表观自我运动，即向量。观察者的眼动被记录下来，以检查视动性眼球震颤对视觉感觉的贡献。结果表明，向量过程中的拍击场向感知的航向方向移动，与向量的强度成正比。这种位移先于对观看条件之间的视向强度的主观估计的差异。因此，甚至在主观估计向量的实际观察之前，就通过测量视动性眼球震颤的搏动场来估计向量的强度。人类感官的每一个曲目都有自己的特点。视觉对听觉的空间优势会导致腹语错觉，而听觉对视觉的时间优势会产生跨通道交互作用，人类在感知具有重叠音调的视觉事件的时间特征时会犯下这种错误。我们发现了一个与这些偏见相反的现象：视觉输入改变了对音调时间特征的感知。在实验中，观察者通过观看虚拟现实系统呈现的视觉显示器的全场运动，对连续呈现的两个音调的时间顺序做出了有偏见的判断。这一结果表明，表观自我运动在时间知觉中起着重要作用。

This research was aimed to investigate the human visual system by using psychophysical and fMRI experiments. In the psychophysical experiments, we used apparent self-motion, vection, elicited by viewing full-field motion presented by an evasive type virtual reality system (CAVE).1. Eye movements of the observers were recorded to examine the contribution of optokinetic nystagmus on the feeling of vection. Results indicated that the beating field during vection was found to displace to the perceived heading direction in proportion to the strength of vection. This displacement preceded the difference in the subjective estimation of the strength of vection between viewing conditions. Thus the strength of vection was estimated by measuring the beating field of optokinetic nystagmus even before the actual observation of the subjective estimation of vection.2. Each repertoire of the human senses has its specialty. While spatial superiority of vision over audition causes ventriloquism illusion, temporal superiority of audition over vision does cross-modal interactions that humans make a mistake in perceiving temporal characteristics of visual events with overlapped tones. We showed a phenomenon opposite to these biases; visual input modifies the perception of temporal characteristics of tones. In the experiment observers made a biased judgment of the temporal-order of two tones presented successively when they felt apparent self-motion (vection) by viewing full-field motion of a visual display presented by a virtual reality system. This result indicated that apparent self-motion plays an influential role in temporal perception.