基于fMRI功能连接度分析正常人相关脑区在运动过程中的参与程度

Connection of motor related cortices in normal subjects:a functional connectivity MR study

目的在运动及静息两种状态下,观察初级运动区(M1)与其他运动相关区域之间功能连接程度,分析特定功能区在运动执行过程中的作用。方法选取6名正常人作为研究对象,进行血氧水平依赖功能磁共振成像(BOLD-fMRI)检查。功能成像分为静息功能、右手运动功能、左手运动功能三部分。运动功能采用Block设计,采取手指顺序对指任务。扫描结果采用统计参数图(SPM2)进行数据分析和脑功能区定位。功能连接度采用时间相关算法,选取运动任务时对应的最强激活点(均为一侧M1区)作为种子点,分别在静息功能数据和运动功能数据中将该种子区与相应全脑做相关分析,计算不同脑区与种子区之间的相关性,以Z值反映其功能连接程度,并观察同一脑区在运动及静息两种状态下与种子点之间Z值的变化。结果在静息状态下,与种子点相关联的区域为双侧躯体感觉运动区(SMC)、辅助运动区(SMA)及同侧顶上小叶(SPL);在运动状态下,与种子点相关联的区域为双侧SMC、SMA、同侧SPL及小脑前叶(ALC);在运动状态下双侧SMC及SMA之间功能联系的Z值较静息状态下普遍增大。结论静息状态下双侧SMC、SMA及同侧SPL之间存在比较稳定的功能联系;运动状态下双侧SMC及SMA之间功能联系增强。运动肢体同侧ALC参与运动任务的执行,但不参与静息状态下运动区之间的功能连接。

Objective To observe the functional connectivity between M1 and other motor cortices in task and rest conditions, and to evaluate how these activations influence human motor performance. Methods Six healthy volunteers were recruited in the study. Each of them underwent BOLD-fMRI examination with a 3.0T MRI scanner. Task-activation fMRI and functional connectivity （resting-state） MRI data were acquired. The former one was designed as a block task of bilateral hand tapping. The data were analyzed by SPM2. A small region of interest which showed the maximal task activation was chosen in the task-activation fMRI maps as seed voxels. The correlation coefficient （expressed as Z score） between seed voxels and all the voxels in the brain was calculated, and the Z score were compared between the task and rest conditions. The statistical methods were rank sum test by SPSS 11.5. Results For resting state, functional connectivity MRI maps based on the seed voxels produced clusters of voxels in regions of bilateral SMC, SMA and ipsilateral SPL while for task conditions, besides those regions, the ALC was also included. For correlation coefficient, the Z score of the task state was much higher than that of resting state. Conclusion In resting state, there is a stable functional connectivity in the region of bilateral SMC, SMA and ipsilateral SPL. When a motor task was performed, the functional connectivity in bilateral SMC and SMA become stronger. The ALC plays a role in motor task but not in resting state.