穴位刺激在脑内诱发的BOLD信号降低效应

目的研究刺激不同穴位在脑内诱发的血氧水平依赖信号降低效应，并探索相关机制。方法对16例健康受试者进行功能性磁共振检查，采用3T磁共振成像系统采集全脑功能像和结构像。功能像连续扫描30层，层厚5mm。扫描时受试者闲目平卧。研究采用体感刺激和静息状态交替方式进行。刺激时对不同穴位进行轻柔、无创、无痛刺激。结果对每一穴位，都观察到体感刺激诱发的血氧水平依赖信号降低效应。相同阈值下，并未发现激活效应。刺激不同穴位诱发的血氧水平依赖信号降低效应集中分布在感觉运动皮质。结论BOLD信号降低效应现象可能由中枢抑制效应产生，以使人脑能够更为清晰地分辨低强度的感觉信号输入。

BOLD signal decreases evoked by acupoint stimulation in brain

Objective It is to study BOLD signal decreases induced by stimulation at different acupoints in brain and to explore its correlated mechanism. Methods 16 healthy subjects received functional MR1 examination with 3T Siemens Magne- tom Trio system. The fMRI data were acquired with a GRE - EPI sequence. Thirty contiguous axial slices with a thickness of 5 mm were acquired for whole-brain coverage. A block-designed method was applied. Different acupoints were stimulated sep- arately. T1 - weighted images were acquired before fMRI data collection. For each stimulus condition, a statistical parametric map of the t statistics and a corresponding contrast map were generated for each subject, and then the group-level t-contrast map was generated in a mixed-effects model. Results Predominant BOLD signal decreases were found for every stimulated acu- point, with various types of spatial distribution. As a common feature, BOLD signal decreases were concentrated across senso- rimotor cortex for all acupoints. Conclusion This phenomenon may be the result of an inhibition process to let human brain discriminate the low-level activation more easily when a subject is receiving a non-painful stimulation.