Honda M, Deiber M P, Ibáñez V, Pascual-Leone A, Zhuang P, Hallett M
Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1428, USA.
Brain. 1998 Nov;121 ( Pt 11):2159-73. doi: 10.1093/brain/121.11.2159.
We examined the dynamic involvement of different brain regions in implicit and explicit motor sequence learning using PET. In a serial reaction time task, subjects pressed each of four buttons with a different finger of the right hand in response to a visually presented number. Test sessions consisted of 10 cycles of the same 10-item sequence. The effects of explicit and implicit learning were assessed separately using a different behavioural parameter for each type of learning: correct recall of the test sequence for explicit learning and improvement of reaction time before the successful recall of any component of the test sequence for implicit learning. Regional cerebral blood flow was measured repeatedly during the task, and a parametric analysis was performed to identify brain regions in which activity was significantly correlated with subjects' performances: i.e. with correct recall of the test sequence or with reaction time. Explicit learning, shown as a positive correlation with the correct recall of the sequence, was associated with increased activity in the posterior parietal cortex, precuneus and premotor cortex bilaterally, also in the supplementary motor area (SMA) predominantly in the left anterior part, left thalamus, and right dorsolateral prefrontal cortex. In contrast, the reaction time showed a different pattern of correlation during different learning phases. During the implicit learning phase, when the subjects were not aware of the sequence, improvement of the reaction time was associated with increased activity in the contralateral primary sensorimotor cortex (SM1). During the explicit learning phase, the reaction time was significantly correlated with activity in a part of the frontoparietal network. During the post-learning phase, when the subjects achieved all components of the sequence explicitly, the reaction time was correlated with the activity in the ipsilateral SM1 and posterior part of the SMA. These results show that different sets of cortical regions are dynamically involved in implicit and explicit motor sequence learning.
我们使用正电子发射断层扫描（PET）研究了不同脑区在隐式和显式运动序列学习中的动态参与情况。在一个序列反应时任务中，受试者用右手的不同手指按下四个按钮中的每一个，以响应视觉呈现的数字。测试环节由相同的10项序列的10个循环组成。分别使用针对每种学习类型的不同行为参数来评估显式学习和隐式学习的效果：显式学习为对测试序列的正确回忆，隐式学习为在成功回忆测试序列的任何组成部分之前反应时间的改善。在任务过程中反复测量局部脑血流量，并进行参数分析以识别与受试者表现显著相关的脑区：即与测试序列的正确回忆或反应时间相关。显式学习表现为与序列的正确回忆呈正相关，与双侧后顶叶皮层、楔前叶和运动前皮层的活动增加有关，也与主要位于左前部的辅助运动区（SMA）、左丘脑和右背外侧前额叶皮层有关。相比之下，反应时间在不同学习阶段呈现出不同的相关模式。在隐式学习阶段，当受试者未意识到序列时，反应时间的改善与对侧初级感觉运动皮层（SM1）的活动增加有关。在显式学习阶段，反应时间与额顶叶网络的一部分活动显著相关。在学习后阶段，当受试者明确完成序列的所有组成部分时，反应时间与同侧SM1和SMA后部的活动相关。这些结果表明，不同的皮层区域集动态参与了隐式和显式运动序列学习。
