不同相干水平视觉运动刺激皮层反应特征的fMRI研究

目的探讨随机点动态运动图作为刺激源是否能够对参与视觉运动觉处理的大脑皮层区域进行准确的功能定位,并在此基础上进一步观测在不同运动相干水平情况下,相关大脑皮层的血氧水平依赖反应特点。方法12名受试者在功能磁共振扫描过程中接受三种不同相干水平的视觉运动刺激(5%,20%,80%),刺激呈现采用组块设计模式。数据经预处理和统计分析得到激活图,并进一步进行兴趣区分析。结果随机点动态运动图作为刺激源能够有效的激活视觉运动觉处理相关视觉皮层区域;以hMT 作兴趣区分析得到三种不同相干水平运动刺激下该区域的激活体积。结论随机点动态运动图刺激能对参与视觉运动觉处理的大脑皮层区域进行准确的功能定位;hMT 的激活体积随着相干水平的提高而减小。

Human cortical response to visual coherent motion: a parametric fMRI study

Objective To investigate the validity of random dot kinematograms in the functional localization of cerebral areas that response to visual coherent motion and to explore the blood oxygenation level dependent response properties of cerebral areas processing visual coherent motion at three different coherence levels. Methods fMRI method was used to map functional neuroanatomy of visual coherent motion perception in 12 normal subjects. The participants performed passive viewing task during fMRI scanning, the stimuli was presented by blocked model. Activation map was obtained after data preprocessing and statistical inference. Finally, the ROI analysis was done. Results The most significant activation was observed in the left and right temporo-parieto-occipital cortex, in the area corresponding to hMT . Area hMT activation volume was obtained through ROI analysis of hMT . Conclusion Cerebral area that processes visual coherent motion signal can be activated significantly by Random dot kinematograms and localized accurately with fMRI techniques; area hMT activation volume decrease when coherence level increases.