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成像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逃避型虚拟现实系统（CAVE）呈现的全场运动而引起的明显自我运动，向量。记录观察者的眼球运动，以检查眼动性震颤对运动感的贡献。结果表明，在对流过程中，跳动场向感知的方向偏移与对流强度成正比。这种位移先于在观看条件之间对对流强度的主观估计的差异。因此，在实际观察到主观估计的视动性眼球震颤之前，通过测量视动性眼球震颤的跳动场来估计视动性眼球震颤的强度。人类的每一种感觉都有其特点。视觉对听觉的空间优势导致腹语错觉，而听觉对视觉的时间优势导致跨模态相互作用，使人类在感知重叠音调的视觉事件的时间特征时犯错误。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，感觉明显的自运动（矢量）时，对连续呈现的两个音调的时间顺序产生了偏差判断。这一结果表明，明显的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.