Attention and stimulus characteristics determine the locus of motor-sequence encoding - A PET study
Attention and stimulus characteristics determine the locus of motor-sequence encoding - A PET study
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DOI：
10.1093/brain/120.1.123
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发表时间：
1997-01-01
期刊：
影响因子：
14.5
通讯作者：
Ivry, R
中科院分区：
文献类型：
--
作者：
Hazeltine, E;Grafton, ST;Ivry, R
PET 揭示了刺激特征对运动学习神经基础的影响。惯用右手的受试者使用颜色编码的刺激执行一系列反应时间任务，以消除习得的眼球运动的可能性。该任务是在两种不同的条件下用右手执行的。在一种情况下，受试者同时执行一项分散注意力的任务。尽管他们确实表现出了学习的行为证据，但他们并没有明确意识到刺激-反应序列。在第二种情况下，没有分散注意力的任务，11 名受试者中的 7 名随后明确意识到了刺激序列。在这两种情况下，学习的代谢相关性是不同的。当学习在双重任务条件下隐式进行时，在左运动皮层、辅助运动皮层以及壳核中观察到与学习相关的变化。这些区域与之前研究中观察到的区域相似，其中刺激是由空间位置提示的。在单任务条件下，右前额叶皮层和前运动皮层以及颞叶发生了代谢变化。在单任务学习期间的空间研究中观察到类似的向右半球的转变。然而，通过颜色刺激明确学习任务会激活更多的腹侧区域。支持运动序列学习的区域取决于刺激特性和注意力限制。
PET revealed the effects of stimulus characteristics on the neural substrate of motor learning. Right-handed subjects performed a serial reaction time task with colour-coded stimuli to eliminate the potential for learned eye-movements. The task was performed with the right hand under two different conditions. In one condition, subjects simultaneously performed a distractor task. Although they did show behavioural evidence of learning, they were not explicitly aware of the stimulus-response sequence. In the second condition, there was no distracter task, and seven out of the 11 subjects then became explicitly aware of the stimulus sequence. Metabolic correlates of learning were distinct in the two conditions. When learning was implicit under dual-task conditions, learning-related changes were observed in left motor and supplementary motor cortex as well as in the putamen. These regions are similar to those observed in a previous study in which the stimuli were cued by spatial position. Under single-task conditions, metabolic changes were found in the right prefrontal cortex and premotor cortex, as well as in the temporal lobe. A similar shift to the right hemisphere was observed in the spatial study during single-task learning. However explicit learning of the task with colour stimuli activated more ventral regions. The areas supporting motor-sequence learning are contingent on both stimulus properties and attentional constraints.