手运动组块设计与事件相关设计的fMRI比较研究

目的:探讨组块和事件相关两种fMRI实验设计在方法学上的差异及其适用范围。方法:对13例健康志愿者进行组块和事件相关两种不同任务模式下右手简单对指运动脑fMRI实验。采用GE 1．5T磁共振全身扫描仪,所获数据应用SPM 99软件进行预处理和统计分析,获取两种实验设计下的脑激活图及各激活区的范围和最大激活强度,对比两种实验设计方法之间的异同。结果:组块设计实验中可见对侧初级运动区(M1)、双侧辅助运动区(SMA)及同侧小脑半球 (CER)明显激活。事件相关设计实验可见对侧M1区及双侧SMA明显激活,小脑未见激活;SMA激活区包括前后两部分,即位于前方的辅助运动前区(Pre-SMA)和后方固有区(SMA Proper);M1区和SMA激活强度较弱、范围较小;事件相关设计可反映各激活区的血流动力学反应过程。结论:两种实验设计均可激活对侧M1区及双侧SMA,以组块设计激活作用更强、范围更大,因此有利于功能区的检出和定位;事件相关设计激活作用较弱,但可以反映功能区的活动细节,有利于研究各功能区之间的相互联系。

A Control Study of Hand Motor fMRI Experiment with Blocked Design and Event Related Design

Objective:To compare the difference and similarities of the block design and event related (ER) design for hand motor fMRI,to analyze their pros and cons. Methods:Thirteen subjects were collected in this experiment,fMRI were acquired by using GE 1. 5T MR scanner. The data were analyzed with SPM 99 software. Coverage functional mapping were acquired and activated voxels and maximum intensity were counted. Results: Using block design, the activated areas were found in contra-lateral primary motor area (M1) ,bilateral supplementary motor areas (SMA) and ipsi-lateral cerebellum. With ER design,The activated areas were found in Ml,SMA,including Pre-SMA and SMA Proper. The cerebellum had no activation,and the activated intensity in the Ml and SMA were stronger in block design than those in ER design. The course of hemodynamic response could be reflected by ER design fMRI. Conclusion: Both the two patterns of design could activate the contra-lateral Ml and bilateral SMA. The activated extent and intensity in the Ml and SMA were stronger in the Block design,providing benefit for the detection and location of the functional areas. The details of the functional activation could be reflected by ER design and was more helpful in the study of relationship among the function areas.