Macar Françoise, Anton Jean-Luc, Bonnet Michel, Vidal Franck
Laboratoire de Neurobiologie de la Cognition, CNRS-UMR 6155, 31 Chemin Joseph-Aiguier, 13402 Marseille cedex 20, France.
Brain Res Cogn Brain Res. 2004 Oct;21(2):206-15. doi: 10.1016/j.cogbrainres.2004.01.005.
Two previous studies in which we recorded slow brain potential shifts over the scalp revealed performance-dependent effects that sustained one prominent model of timing mechanisms. These effects seemed to be derived from the supplementary motor area (SMA). Event-related functional magnetic resonance imagery (fMRI) was used to check this hypothesis. Brain activations were contrasted in Time production and (control) Force production tasks involving left-hand responding. These tasks, presented in mixed order, were designed to be of equivalent difficulty and involve comparable levels of attention. Several brain areas were activated in both tasks relative to baseline: the SMA, the putamen, and the lateral cerebellum. Contrasts between tasks gave clear-cut differences. Activations specific to the Time task were found in the SMA proper and the left primary motor cortex. The Force task activated the right sensorimotor cortex and the left cerebellum, and, bilaterally, the infero-parietal cortex and the insula. The main result, i.e. prominent activation of the SMA proper in relation to temporal production, corroborates our previous studies based on slow cortical potentials. The data are referred to current evidence suggesting that timing processes are subtended by a striato-thalamo-cortical pathway including the SMA.
我们之前进行的两项研究记录了头皮上缓慢的脑电电位变化，结果揭示了与表现相关的效应，这些效应支持了一种重要的计时机制模型。这些效应似乎源自辅助运动区（SMA）。我们使用事件相关功能磁共振成像（fMRI）来检验这一假设。在涉及左手反应的时间生产任务和（对照）力量生产任务中对比脑激活情况。这些任务以混合顺序呈现，设计为具有同等难度且涉及相当水平的注意力。相对于基线，两项任务均激活了几个脑区：辅助运动区、壳核和外侧小脑。任务之间的对比产生了明显差异。在特定的时间任务中，辅助运动区本身和左侧初级运动皮层出现激活。力量任务激活了右侧感觉运动皮层和左侧小脑，双侧的下顶叶皮层和脑岛也被激活。主要结果，即辅助运动区本身相对于时间生产有显著激活，证实了我们之前基于缓慢皮层电位的研究。这些数据参考了当前的证据，表明计时过程由包括辅助运动区在内的纹状体 - 丘脑 - 皮层通路支撑。
