Frontal and parietal networks for conditional motor-learning: A positron emission tomography study
Frontal and parietal networks for conditional motor-learning: A positron emission tomography study
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DOI：
10.1152/jn.1997.78.2.977
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发表时间：
1997-08-01
影响因子：
2.5
通讯作者：
Hallett, M
中科院分区：
文献类型：
--
作者：
Deiber, MP;Wise, SP;Hallett, M
对非人类灵长类动物的研究表明，运动前区（PM）和前额叶（PF）区对于将一组刺激任意映射到一组反应是必要的。然而，正电子发射断层扫描（PET）测量局部脑血流量（rCBF）在人类受试者未能揭示预测的rCBF的变化，在这样的行为。因此，我们研究了rCBF，而受试者学习两个任意映射任务。在条件运动任务中，视觉刺激指示四个方向中的哪一个移动操纵杆（用右手，优势手）。在评估任务中，受试者在预定的方向上移动操纵杆，以报告箭头是否指向与给定刺激相关的方向。对于这两项任务，都有三个规则：对于非空间规则，每个刺激内的模式决定了正确的方向;对于空间规则，刺激的位置决定了正确的方向;对于固定反应规则，无论模式如何，移动方向都是恒定的或其位置。对于非空间的规则，性能的评价任务导致学习相关的增加，rCBF在尾侧和腹侧部分的运动前皮质（PMVC，区6），双侧，以及在壳核和扣带运动区（CM，区24）的左半球。在以下几个区域观察到rCBF降低：左腹眶前额叶皮质（PFv，区域47/12）、左外侧小脑半球，以及右半球PM的背侧和喙侧（PMdr，区域6）、背侧PF（PFd，区域9）和后顶叶皮质（区域39/40）。在条件运动任务的性能，只有减少顶叶区。对于空间规则，没有rCBF的变化达到显着的评价任务，但在条件运动任务，腹侧和头侧运动前区（PMvr，区6），背外侧前额叶皮层（PFDL，区46），和后顶叶皮层（区39/40）在学习过程中显示下降的rCBF，所有在右半球。这些数据证实了预测的rCBF的变化，在任意映射任务的前运动区和前额叶区，并建议一个广泛的额顶叶网络可能会显示出减少突触活动的任意规则变得更加熟悉。
Studies on nonhuman primates show that the premotor (PM) and prefrontal (PF) areas are necessary for the arbitrary mapping of a set of stimuli onto a set of responses. However, positron emission tomography (PET) measurements of regional cerebral blood flow (rCBF) in human subjects have failed to reveal the predicted rCBF changes during such behavior. We therefore studied rCBF while subjects learned two arbitrary mapping tasks. In the conditional motor task, visual stimuli instructed which of four directions to move a joystick (with the right, dominant hand). In the evaluation task, subjects moved the joystick in a predetermined direction to report whether an arrow pointed in the direction associated with a given stimulus. For both tasks there were three rules: for the nonspatial rule, the pattern within each stimulus determined the correct direction; for the spatial rule, the location of the stimulus did so; and for the fixed-response rule, movement direction was constant regardless of the pattern or its location. For the nonspatial rule, performance of the evaluation task led to a learning-related increase in rCBF in a caudal and ventral part of the premotor cortex (PMvc, area 6), bilaterally, as well as in the putamen and a cingulate motor area (CM, area 24) of the left hemisphere. Decreases in rCBF were observed in several areas: the left ventro-orbital prefrontal cortex (PFv, area 47/12), the left lateral cerebellar hemisphere, and, in the right hemisphere, a dorsal and rostral aspect of PM (PMdr, area 6), dorsal PF (PFd, area 9), and the posterior parietal cortex (area 39/40). During performance of the conditional motor task, there was only a decrease in the parietal area. For the spatial rule, no rCBF change reached significance for the evaluation task, but in the conditional motor task, a ventral and rostral premotor region (PMvr, area 6), the dorsolateral prefrontal cortex (PFdl, area 46), and the posterior parietal cortex (area 39/40) showed decreasing rCBF during learning, all in the right hemisphere. These data confirm the predicted rCBF changes in premotor and prefrontal areas during arbitrary mapping tasks and suggest that a broad frontoparietal network may show decreased synaptic activity as arbitrary rules become more familiar.