Study on information processing of the human visual system

本文应用电生理学和心理物理学方法研究了人眼视觉通路的信息加工过程，得到以下结果。1)正常老年人和视觉障碍患者的对比敏感度功能（CSF）：老年人在高空间频率下CSF降低，视神经炎患者CSF异常与VEP异常高度相关。在接受多种药物治疗的癫痫患者中观察到CSF恶化。这些结果表明，CSF在评估视功能方面是有用的。2)正常人和视功能障碍患者的视网膜电图（ERG）和视觉诱发电位（VEP）：均匀场刺激的ERG与图形反转刺激的ERG不同，前者起源于视网膜的节前细胞，后者起源于视网膜的节细胞。视觉诱发电位的刺激参数如亮度、对比度、检查大小和时间频率等对决定视觉诱发电位反应是非常重要的。VEP（N100）的额叶负波可能在额叶中产生，作为视觉注意力的指标。稳态闪光视觉诱发电位发现阿尔茨海默型痴呆患者存在时间频率缺陷。利用等亮度彩色正弦光栅和视运动显示，可以刺激平行视觉通路。3)正常受试者的双眼视觉和视觉辨别：通过随机点立体图评估正常受试者的双眼视觉，并记录视觉辨别的事件相关电位。但其意义还有待进一步研究。

The information processing of the human visual pathways was studied by using electrophysiological and psychophysical methods.Following results were obtained. 1)Contrast sensitivity function (CSF) in normal aging and patients with visual disorders: Decreased CSF in aged people at high spatial frequencies was found. There was a high correlation between abnormal CSF and abnormal VEP in patients with optic neuritis. Deterioration of CSF was observed in patients with epilepsy treated with polypharmacy. These results indicate the usefulness of CSF in assessing the visual function. 2)Electroretinogram (ERG) and visual evoked potential (VEP) in normal subjects and patients with visual dysfunction: ERGs to uniform-field stimulation are different from those to patten-reversal stimulation, indicating that the former originates from the pre-ganglionic cells and the latter from the ganglion cells in the retina. Stimulus parameters of VEPs such as luminance, contrast, check size and temporal frequency were very important to determine the VEP responses. Frontal negativity of VEPs (N100) may be generated in the frontal lobe as a indicator of visual attention. Temporal frequency deficit in patients with dementia of Alzheimer type was found by steady-state flash VEPs. By using isoluminant chromatic sinusoidal gratings and apparent motion display, it is possible to stimulate the parallel visual pathways. 3)Binocular vision and visual discrimination in normal subjects: Binocular vision was assessed by random dot stereograms in normal subjects and event-related potentials to visual discrimination was recorded. But the further studies are required to clarity their significance.