Objectives: Studies on the influence of motor imagery (MI) on brain structure and function are limited to traditional imaging techniques and the mechanism for MI therapy is not clear. By observing the brain activation mode during MI and motor execution (ME) in healthy adults, this study aims to use near-infrared brain imaging technology to provide theoretical basis for the treatment of MI.
Methods: A total of 30 healthy adults recruited to the public from June 2021 to August 2021. The MI and ME of the right knee movement served as the task mode. Block design was repeated 5 times alternately in a 20 s task period and a 30 s resting period. The activation patterns of brain regions were compared between the 2 tasks, and the regression coefficient was calculated to reflect the activation intensity of each brain region by Nirspark and SPSS 23.0 softwares.
Results: Lane 2, 3, 4, 5, 7, 9, 19, 20, 21, 24, 25, 26, 27, 32, 33, and 34 were significantly activated during the ME task (P<0.05, corrected by FDR) and lane 2, 5, 9, 16, 27, 29, 33, 34, and 35 were significantly activated during the MI task (P<0.05, corrected by FDR). According to the channel brain region registration information, the brain region activation pattern was similar during both MI and ME tasks in healthy adults, including left primary motor cortex (LM1), left primary sensory cortex (LS1), prefrontal pole, Broca area, and right supramarginal gyrus. Both LM1 and left pre-motor cortex (LPMC) were activated during MI in healthy adults, whereas dorsolateral prefrontal cortex (DLPFC) and only LM1 of the motor region were activated during ME. Compared to MI, the activation intensity of left sensory and left motor cortex was significantly enhanced in ME, and that of left and right prefrontal cortex especially left and right pars triangularis Broca's area (P<0.001, corrected by FDR) were significantly enhanced.
Conclusions: The rationality of MI therapy is proved by functional near-infrared spectroscopy. The involvement of DLPFC in motor decision-making may regulate the two-way feedback of premoter cortex-M1 during ME; and Broca area, closely related to the motor program understanding, participates in MI and ME.
目的: 运动想象(motor imagery，MI)对脑结构和功能影响的研究仅限于传统影像学技术，MI疗法的机制至今不明确。本研究采用近红外脑功能成像技术对比健康成人MI与运动执行(motor execution，ME)时的脑区激活模式，旨在为MI疗法提供神经影像学理论依据。方法: 选取2021年6月至8月面向社会公开招募的30例健康成年人，以“屈伸右膝”动作的MI和ME作为任务模式，采用20 s任务期，30 s休息期，交替重复5次的设计模式，利用Nirspark和SPSS 23.0软件分析2种任务下脑区激活模式的异同，并计算回归系数以反映各脑区的激活强度。结果: 健康成人在ME任务期2、3、4、5、7、9、19、20、21、24、25、26、27、32、33、34通道被显著激活(经FDR校正，P<0.05)；MI任务期2、5、9、16、27、29、33、34、35通道被显著激活(经FDR校正，P<0.05)。根据通道脑区配准信息，健康成人在MI与ME任务期激活的脑区相似，分别有左初级运动皮层(left primary motor cortex，LM1)、左初级感觉皮层(left primary sensory cortex，LS1)、前额极、布洛卡氏区和右侧缘上回；健康成人在MI任务期LM1与左前运动皮层均有激活；而在ME任务期背外侧前额叶(dorsolateral prefrontal cortex，DLPFC)激活，运动区仅有LM1激活。相较于MI，健康成人在ME任务期左感觉与左运动皮层激活强度均明显增强(均P<0.05)，左、右前额叶特别是左、右布洛卡氏区的激活强度显著增强(经FDR校正，P<0.001)。结论: 近红外脑功能成像证实了MI疗法的合理性；在ME任务期DLPFC参与运动决策，并可能参与前运动皮层-M1的双向反馈调节；布洛卡氏区参与ME与MI，与运动行为的理解密切相关。.
Keywords: functional near-infrared spectroscopy; healthy adult; motor execution; motor imagery.