Poldrack Russell A, Sabb Fred W, Foerde Karin, Tom Sabrina M, Asarnow Robert F, Bookheimer Susan Y, Knowlton Barbara J
Department of Psychology, University of California, Los Angeles, Los Angeles, California 90095-1563, USA.
J Neurosci. 2005 Jun 1;25(22):5356-64. doi: 10.1523/JNEUROSCI.3880-04.2005.
Acquisition of a new skill is generally associated with a decrease in the need for effortful control over performance, leading to the development of automaticity. Automaticity by definition has been achieved when performance of a primary task is minimally affected by other ongoing tasks. The neural basis of automaticity was examined by testing subjects in a serial reaction time (SRT) task under both single-task and dual-task conditions. The diminishing cost of dual-task performance was used as an index for automaticity. Subjects performed the SRT task during two functional magnetic imaging sessions separated by 3 h of behavioral training over multiple days. Behavioral data showed that, by the end of testing, subjects had automated performance of the SRT task. Before behavioral training, performance of the SRT task concurrently with the secondary task elicited activation in a wide network of frontal and striatal regions, as well as parietal lobe. After extensive behavioral training, dual-task performance showed comparatively less activity in bilateral ventral premotor regions, right middle frontal gyrus, and right caudate body; activity in other prefrontal and striatal regions decreased equally for single-task and dual-task conditions. These data suggest that lateral and dorsolateral prefrontal regions, and their corresponding striatal targets, subserve the executive processes involved in novice dual-task performance. The results also showed that supplementary motor area and putamen/globus pallidus regions showed training-related decreases for sequence conditions but not for random conditions, confirming the role of these regions in the representation of learned motor sequences.
新技能的习得通常与对行为进行刻意控制的需求减少相关联，从而导致自动化的发展。根据定义，当一项主要任务的执行受其他同时进行的任务影响最小时，就实现了自动化。通过在单任务和双任务条件下对受试者进行序列反应时（SRT）任务测试，研究了自动化的神经基础。双任务执行成本的降低被用作自动化的指标。受试者在两次功能磁共振成像实验中执行SRT任务，两次实验之间间隔多天进行3小时的行为训练。行为数据表明，到测试结束时，受试者已使SRT任务的执行自动化。在行为训练之前，SRT任务与次要任务同时执行时，会在额叶、纹状体区域以及顶叶的广泛网络中引发激活。经过广泛的行为训练后，双任务执行在双侧腹侧运动前区、右侧额中回和右侧尾状体内显示出相对较少的活动；在其他前额叶和纹状体区域，单任务和双任务条件下的活动均同等减少。这些数据表明，外侧和背外侧前额叶区域及其相应的纹状体靶点，参与了新手双任务执行中涉及的执行过程。结果还表明，辅助运动区和壳核/苍白球区域在序列条件下显示出与训练相关的减少，但在随机条件下则没有，这证实了这些区域在学习到的运动序列表征中的作用。
