Makuuchi Michiru
Division of Human Brain Research, Department of Neuroscience, Karolinska Institute, Retzius väg 8, A3; 3 Stockholm 171 77, Sweden.
Cereb Cortex. 2005 May;15(5):563-70. doi: 10.1093/cercor/bhh157. Epub 2004 Aug 18.
Some neuroimaging studies have reported activation by imitation in the left Brodmann area 44 (BA 44), a part of Broca's area considered to be a neural substrate for speech production. However, in these previous studies the subjects were required to perform the same movements repeatedly so that the experimental stimuli could be viewed as cues when to do the given movements rather than a specification of what to do. Activation in the left BA 44 has also been observed in delayed motor execution tasks. This may confound the activity in BA 44 for imitation tasks used in the former studies. We tested the involvement of bilateral BA 44 and BA 45 in imitation and delayed execution tasks by functional magnetic resonance imaging with cytoarchitectonically defined BA 44 and BA 45 as volumes of interest. Our tasks required the subjects to perform a transformation from visual information (photographs of hand postures or symbolic specification of the postures) into a new hand movement in each trial. A three-way analysis of variance was performed with factors instruction, execution timing and area. The results revealed significant main effect by execution timing and by area, but not by instruction. We conclude that Broca's area does not play a pivotal role in imitation.
一些神经影像学研究报告称,在左侧布罗德曼区44(BA 44),即被认为是言语产生神经基质的布洛卡区的一部分,存在模仿激活现象。然而,在这些先前的研究中,受试者被要求反复执行相同的动作,因此实验刺激可被视为何时执行给定动作的提示,而非对做什么的具体规定。在延迟运动执行任务中也观察到左侧BA 44的激活。这可能会混淆先前研究中用于模仿任务的BA 44的活动。我们通过功能磁共振成像,将细胞构筑学定义的BA 44和BA 45作为感兴趣区域,测试了双侧BA 44和BA 45在模仿和延迟执行任务中的参与情况。我们的任务要求受试者在每次试验中从视觉信息(手部姿势照片或姿势的符号说明)转换为新的手部动作。进行了一项三因素方差分析,因素包括指令、执行时间和区域。结果显示执行时间和区域有显著主效应,但指令没有。我们得出结论,布洛卡区在模仿中不发挥关键作用。