Jueptner M, Stephan K M, Frith C D, Brooks D J, Frackowiak R S, Passingham R E
Wellcome Department of Cognitive Neurology, Institute of Neurology, London, United Kingdom.
J Neurophysiol. 1997 Mar;77(3):1313-24. doi: 10.1152/jn.1997.77.3.1313.
We used positron emission tomography to study new learning and automatic performance in normal volunteers. Subjects learned sequences of eight finger movements by trial and error. In a previous experiment we showed that the prefrontal cortex was activated during new learning but not during during automatic performance. The aim of the present experiment was to see what areas could be reactivated if the subjects performed the prelearned sequence but were required to pay attention to what they were doing. Scans were carried out under four conditions. In the first the subjects performed a prelearned sequence of eight key presses; this sequence was learned before scanning and was practiced until it had become overlearned, so that the subjects were able to perform it automatically. In the second condition the subjects learned a new sequence during scanning. In a third condition the subjects performed the prelearned sequence, but they were required to attend to what they were doing; they were instructed to think about the next movement. The fourth condition was a baseline condition. As in the earlier study, the dorsal prefrontal cortex and anterior cingulate area 32 were activated during new learning, but not during automatic performance. The left dorsal prefrontal cortex and the right anterior cingulate cortex were reactivated when subjects paid attention to the performance of the prelearned sequence compared with automatic performance of the same task. It is suggested that the critical feature was that the subjects were required to attend to the preparation of their responses. However, the dorsal prefrontal cortex and the anterior cingulate cortex were activated more when the subjects learned a new sequence than they were when subjects simply paid attention to a prelearned sequence. New learning differs from the attention condition in that the subjects generated moves, monitored the outcomes, and remembered the responses that had been successful. All these are nonroutine operations to which the subjects must attend. Further analysis is needed to specify which are the nonroutine operations that require the involvement of the dorsal prefrontal and anterior cingulate cortex.
我们采用正电子发射断层扫描技术来研究正常志愿者的新学习和自动执行情况。受试者通过反复试验学习八指动作序列。在之前的一项实验中，我们发现前额叶皮质在新学习过程中被激活，但在自动执行过程中未被激活。本实验的目的是观察如果受试者执行预先学习的序列，但被要求注意自己正在做的事情，哪些区域会被重新激活。扫描在四种条件下进行。第一种条件下，受试者执行预先学习的八个按键序列；该序列在扫描前学习，并练习到过度学习，以便受试者能够自动执行。第二种条件下，受试者在扫描过程中学习新序列。第三种条件下，受试者执行预先学习的序列，但被要求注意自己正在做的事情；他们被指示思考下一个动作。第四种条件是基线条件。与早期研究一样，背侧前额叶皮质和前扣带回32区在新学习过程中被激活，但在自动执行过程中未被激活。与同一任务的自动执行相比，当受试者注意预先学习序列的执行时，左侧背侧前额叶皮质和右侧前扣带回皮质被重新激活。有人认为关键特征是受试者被要求注意其反应的准备。然而，与受试者只是简单注意预先学习的序列相比，当受试者学习新序列时，背侧前额叶皮质和前扣带回皮质的激活程度更高。新学习与注意条件的不同之处在于，受试者产生动作、监测结果并记住成功的反应。所有这些都是受试者必须注意的非常规操作。需要进一步分析来确定哪些是需要背侧前额叶和前扣带回皮质参与的非常规操作。
