Kawashima R, Roland P E, O'Sullivan B T
Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
J Neurosci. 1994 Jun;14(6):3462-74. doi: 10.1523/JNEUROSCI.14-06-03462.1994.
The purpose of this study was to examine the functional organization of motor cortices in the human brain involved in reaching and visuomotor learning. All subjects were asked to learn the positions of seven circular targets projected on a screen. Each time the targets were turned off, they were required to close their eyes and keep them closed, and, after a delay, to point to the center of the targets in a prescribed order using their right hand. The regional cerebral blood flow (rCBF) was measured with 15O-butanol and positron emission tomography in 20 subjects during a rest state, an initial learning stage, and a later learning stage. Ten subjects constituted the reaching group in which rCBF was measured during actual reaching; the 10 other subjects constituted the preparation group in which rCBF was measured in the delay period between target exposure and actual reaching. Individual subtraction images (each stage minus rest) were calculated and transformed into a standard size and shape brain image by the adjustable computerized brain atlas and averaged, after which significant changes of rCBF were identified. In all reaching and preparation for reaching phases, cortical fields were activated in the left primary motor area (M1) and the left premotor area (PMA). Within M1, fields active in the delay phases were adjacent to the fields active only during actual reaching movements. During the course of learning, additional fields of activity appeared in both M1 and PMA. The results indicate that three types of fields occur in M1 and PMA: (1) fields directly engaged in the efferent control of peripheral muscle contraction, (2) fields engaged in preparatory activity for reaching, and (3) fields appearing after learning of the task has taken place.
本研究的目的是检查人类大脑中参与伸手动作和视觉运动学习的运动皮层的功能组织。所有受试者都被要求学习投射在屏幕上的七个圆形目标的位置。每次目标关闭后，要求他们闭上眼睛并保持闭眼状态，经过一段时间延迟后，用右手按规定顺序指向目标的中心。在20名受试者处于静息状态、初始学习阶段和后期学习阶段时，使用15O - 丁醇和正电子发射断层扫描测量局部脑血流量（rCBF）。10名受试者构成伸手组，在实际伸手过程中测量rCBF；另外10名受试者构成准备组，在目标暴露与实际伸手之间的延迟期测量rCBF。计算个体减法图像（每个阶段减去静息状态），并通过可调节的计算机脑图谱将其转换为标准大小和形状的脑图像并进行平均，之后确定rCBF的显著变化。在所有伸手和伸手准备阶段，左侧初级运动区（M1）和左侧运动前区（PMA）的皮质区域被激活。在M1内，在延迟阶段活跃的区域与仅在实际伸手运动期间活跃的区域相邻。在学习过程中，M1和PMA中出现了额外的活动区域。结果表明，M1和PMA中存在三种类型的区域：（1）直接参与外周肌肉收缩传出控制的区域，（2）参与伸手准备活动的区域，（3）在任务学习后出现的区域。
