Development of a new method for measuring higher brain function - integrated measuring system by fMRI and MEG -

本研究的目的是建立一种新的综合应用功能磁共振成像、脑磁图和近红外光谱的测量系统来评估高级脑功能。首先，通过fMRI观察到电刺激双侧正中神经时激活的BOLD信号。在无延迟、30毫秒延迟和100毫秒延迟三种情况下，评估激活的BOLD信号的分布。结果发现，在30ms的延迟条件下，初级感觉区的激活面积最小。脑磁图研究显示，在30毫秒的延迟条件下，没有观察到76毫秒的波。其次，使用3-特斯拉功能磁共振对正常右撇子受试者的大脑功能进行了评估。有趣的是，在左手与纸-石头-剪刀打成平局时，右侧SMA被更强烈地激活，而左侧SMA在左手与纸-石头-剪刀打成平局时被更强烈地激活。这些发现表明，左侧SMA可能与受试者大脑中的刻板印象的抑制和冲突的监控有关。最后，我们用近红外光谱评价了重度颈动脉狭窄患者手术前后血中血红蛋白浓度的变化。手术前，在握手作业中，初级手周围运动区的血色素浓度明显升高，但手术后血色素浓度消失。我们的研究表明，还需要进一步的研究来阐明更详细的高级脑功能，为了实现这一目标，比较电刺激双侧正中神经时fMRI和MEG的激活脑区分布尤为重要。

The aim of this study is to establish a new integrated measuring system by fMRI, MEG and NIRS for evaluation of higher brain function. First, activated BOLD signals were observed during electrostimulation on bilateral median nerves by fMRI. Distributions of activated BOLD signals were evaluated in the three conditions, no delay, 30 msec delay and 100 msec delay. As a result, the smallest activated area was observed at the primary sensory area in the 30 msec delay condition. A MEG study revealed that no waves at 76 msec were observed in the 30 msec delay condition. Second, it was evaluated how the brain functions during loss-resulting or tie-resulting pursuant paper-rock-scissors with the dominant or non-dominant hands, using a 3-tesla functional MRI in normal right-handed subjects. Interestingly, the right SMA was activated more strongly during tie-resulting pursuant paper-rock-scissors with the left hand, while the left SMA was activated more strongly during loss-resulting pursuant paper-rock-scissors with the left hand. These findings suggest that the left SMA might be associated with inhibition of stereotypical performance and monitoring of conflict in the subject's mind. Last, we evaluated changes in blood concentration of hemoglobin by NIRS in the patients with severe carotid arterial stenosis before and after surgery. Before surgery, an evident elevation of blood concentration of hemoglobin was observed at the periprimary hand motor area during hand grasp task, although it disappeared after surgery. Our study revealed that further investigation is required to clarify more detailed higher brain functions, and for the achievement of this goal, it was especially important to compare the distributions of activated brain area by between fMRI and MEG during electrostimulation on bilateral median nerves.