Cincotta Corinna M, Seger Carol A
Colorado State University, Fort Collins, CO 80523, USA.
J Cogn Neurosci. 2007 Feb;19(2):249-65. doi: 10.1162/jocn.2007.19.2.249.
Convergent evidence from functional imaging and from neuropsychological studies of basal ganglia disorders indicates that the striatum is involved in learning to categorize visual stimuli with feedback. However, it is unclear which cognitive process or processes involved in categorization is or are responsible for striatal recruitment; different regions of the striatum have been linked to feedback processing and to acquisition of stimulus-category associations. We examined the effect of the presence of feedback during learning on striatal recruitment by comparing feedback learning with observational learning of an information integration task. In the feedback task, participants were shown a stimulus, made a button press response, and then received feedback as to whether they had made the correct response. In the observational task, participants were given the category label before the stimulus appeared and then made a button press indicating the correct category membership. A region-of-interest analysis was used to examine activity in three regions of the striatum: the head of the caudate, body and tail of the caudate, and the putamen. Activity in the left head of the caudate was modulated by the presence of feedback: The magnitude of activation change was greater during feedback learning than during observational learning. In contrast, the bilateral body and tail of the caudate and the putamen were active to a similar degree in both feedback and observational learning. This pattern of results supports a functional dissociation between regions of the striatum, such that the head of the caudate is involved in feedback processing, whereas the body and tail of the caudate and the putamen are involved in learning stimulus-category associations. The hippocampus was active bilaterally during both feedback and observational learning, indicating potential parallel involvement with the striatum in information integration category learning.
来自功能成像以及基底神经节疾病神经心理学研究的趋同证据表明，纹状体参与了在反馈的情况下学习对视觉刺激进行分类。然而，尚不清楚分类过程中涉及的哪些认知过程导致了纹状体的激活；纹状体的不同区域与反馈处理以及刺激类别关联的习得有关。我们通过比较信息整合任务的反馈学习和观察学习，研究了学习过程中反馈的存在对纹状体激活的影响。在反馈任务中，向参与者展示一个刺激，参与者按下按钮做出反应，然后收到关于他们是否做出正确反应的反馈。在观察任务中，在刺激出现之前向参与者给出类别标签，然后参与者按下按钮指出正确的类别归属。使用感兴趣区域分析来检查纹状体三个区域的活动：尾状核头部、尾状核体部和尾部以及壳核。尾状核左头部的活动受到反馈的调节：反馈学习期间激活变化的幅度大于观察学习期间。相比之下，尾状核的双侧体部和尾部以及壳核在反馈学习和观察学习中的活跃程度相似。这种结果模式支持了纹状体区域之间的功能分离，即尾状核头部参与反馈处理，而尾状核的体部和尾部以及壳核参与学习刺激类别关联。在反馈学习和观察学习期间，海马体双侧均处于活跃状态，表明在信息整合类别学习中可能与纹状体平行参与。
