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

本研究旨在建立一种新的功能磁共振成像、脑磁图和近红外光谱综合测量系统，用于脑高级功能的评估。首先，通过fMRI观察双侧正中神经电刺激时激活的BOLD信号。在无延迟、30 msec延迟和100 msec延迟三种情况下，评估激活BOLD信号的分布。结果表明，延迟30 msec时，激活最小的区域位于初级感觉区。脑磁图研究显示，在延迟30毫秒的情况下，76毫秒时没有观察到波。其次，对正常右撇子受试者使用3-特斯拉功能核磁共振成像（MRI），评估他们在使用优势手或非优势手时，在导致损失或平局的情况下，大脑的功能如何。有趣的是，在用左手玩剪刀布-石头-布时，右侧SMA被更强烈地激活，而在用左手玩剪刀布-石头-布时，左侧SMA被更强烈地激活。这些发现表明，左侧SMA可能与抑制刻板印象行为和监控受试者头脑中的冲突有关。最后，我们通过近红外光谱评估了严重颈动脉狭窄患者手术前后血血红蛋白浓度的变化。术前，手抓任务时，手周围运动区血红蛋白血浓度明显升高，术后消失。我们的研究表明，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，比较双侧正中神经电刺激时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.