皮层信息加工依赖神经元兴奋和抑制系统的相互作用，因抑制系统的构成具有复杂性和其在皮层内信息加工过程中的重要性，抑制功能的改变会造成多种脑功能障碍。视觉运动知觉涉及复杂的空间、时间信息整合，依赖抑制性神经元的精细调控，更容易受到脑功能障碍的影响。此外，视觉是脑功能研究中最为成熟的，有许多成熟的实验范式可以用于脑功能障碍的研究。本研究以反映皮层内抑制功能的视觉运动方向互斥范式以及反映皮层间抑制功能的运动光栅方向辨别任务来研究脑功能障碍患者视觉皮层抑制功能的变化， 为脑功能障碍的神经机制提供证据；并且为寻找改善老年人生活质量的方法和寻找诊断精神疾病的手段提供依据。
本文第一部分主要考察了视觉运动方向互斥任务与相关因素之间的关系。 实验一发现两个运动方向的朝向不会影响运动方向互斥效应值的大小。实验二在同一批被试中分别收集了这两种任务的效应值，并做相关性分析，结果发现没有相关性，因此进一步验证这两种任务所反映的抑制效应属于独立的加工机制。实验三中，使用WSCT 和 N-back实验任务探测被试的认知功能，并与运动方向互斥效应值进行相关性分析，结果发现没有相关性。因此脑功能障碍患者认知功能障碍并不能成为其任务表现能力降低的影响因素。
本文第二部分主要考察了老年人视觉皮层内和皮层间抑制功能的变化。 实验四中，我们使用视觉运动互斥实验范式探测到老年人视觉运动方向互斥效应较年轻人增加，提示老年人视觉皮层内抑制功能增加。实验五中，我们使用运动光栅外周抑制实验范式探测到老年人高对比度运动光栅抑制能力较正常人降低，提示老年人视觉皮层间抑制能力降低。因此，老年化对视觉皮层抑制功能的影响属于非均一化，即不同的抑制功能受老年化的影响不同。
本文第三部分主要考察了精神疾病患者视觉皮层内抑制功能的变化。实验六中，我们使用视觉运动互斥实验范式探测到精神分裂症患者视觉运动方向互斥效应较正常对照组增加，提示精神分裂症视觉皮层内抑制功能增加。实验七中，我们使用视觉运动互斥实验范式探测到双相情感障碍视觉运动方向互斥效应较正常对照组增加，提示双相情感障碍视觉皮层内抑制功能增加。我们将这两类患者的症状得分与运动方向互斥效应值进行相关性分析，结果没有发现相关性，因此皮层内抑制功能的变化不具有症状相关性。
综上，本研究主要发现老年人、精神分裂症患者和双相情感障碍患者视觉皮层内抑制功能增强，老年人运动方向互斥效应增强体现在更多角度上；而精神分裂症和双相情感障碍患者的运动方向互斥效应并无显著差别。此外，结合前人研究结果，我们发现这三类脑功能障碍群体脑内不同的抑制功能有不同的变化趋势。

The interaction of neural inhibition and excitation is the basis of cortical information processing. Since the inhibitory system is complex and plays a vital role in information processing, alterations of inhibition cause many kinds of brain dysfunctions. Previous studies have suggested that aging and mental disease generally reduces  neuronal inhibition in  the  visual system. Here, we investigated  how aging, schizophrenia, and bipolar disease  affect intra-cortical  inhibition  using a motion direction discrimination task based on  the  motion repulsion phenomenon. Motion repulsion refers to the phenomenon  by which  observers overestimate the perceived angle when two superimposed dot patterns  are  moving at an acute angle. The misperception has been interpreted as mutual inhibition between nearby direction-tuned neurons within the same cortical area.
We found  that elderly  exhibited much stronger motion repulsion  than  young adults. Our results  indicate that  intra-cortical  inhibition  increases with age. We then compared this effect to aging effect on feedback inhibition, which is measured by the surround suppression paradigm  previously  used by Betts and  colleagues. We found that  elderly  showed  less change  in  the  discrimination threshold when the size  of  a high-contrast drifting Gabor was increased,  indicating  reduced  surround suppression compared  to young adults. Our  results  suggest  that aging does not always lead to a decrease of neuronal inhibition in the visual system.
We found  that elderly  exhibited much stronger motion repulsion  than  young adults. Our results  indicate that  intra-cortical  inhibition  increases with age. We then compared this effect to aging effect on feedback inhibition, which is measured by the surround suppression paradigm  previously  used by Betts and  colleagues. We found that  elderly  showed  less change  in  the  discrimination threshold when the size  of  a high-contrast drifting Gabor was increased,  indicating  reduced  surround suppression compared  to young adults. Our  results  suggest  that aging does not always lead to a decrease of neuronal inhibition in the visual system.
We  then  used motion repulsion to explore the alteration of intra-area mutual inhibition in schizophrenia and bipolar patients. We found enhanced motion repulsion in patient subjects compared to normal  controls in both of the diseases. We also looked for correlations between motion repulsion and PANSS scores in schizophrenia patients, and found no significance. There was no significant correlation  between motion repulsion and depression and anxiety scores in bipolar patients.  
In sum, our results suggest that intra-area mutual inhibition enhanced in the aged, schizophrenia patients, and bipolar patients. Compared to the mental disease patients, the aged show more generalized enhancement, but there is no significant difference between schizophrenia and bipolar patients. Motion repulsion can probe brain dysfunction, but it cannot distinguish different diseases.