Department of Psychological Sciences, Texas Tech University, Box 42051, Lubbock, TX 79409-2051, United States.
Neuroimage. 2018 Feb 1;166:19-31. doi: 10.1016/j.neuroimage.2017.10.057. Epub 2017 Oct 28.
Category learning is a critical neurobiological function that allows organisms to simplify a complex world. Rostrolateral prefrontal cortex (rlPFC) is often active in neurobiological studies of category learning; however, the specific role this region serves in category learning remains uncertain. Previous category learning studies have hypothesized that the rlPFC is involved in switching between rules, whereas others have emphasized rule abstraction and evaluation. We aimed to clarify the role of rlPFC in category learning and dissociate switching and evaluation accounts using two common types of category learning tasks: matching and classification. The matching task involved matching a reference stimulus to one of four target stimuli. In the classification task, participants were shown a single stimulus and learned to classify it into one of two categories. Matching and classification are similar but place different demands on switching and evaluation. In matching, a rule can be known with certainty after a single correct answer. In classification, participants may need to evaluate evidence for a rule even after an initial correct response. This critical difference allows isolation of evaluative functions from switching functions. If the rlPFC is primarily involved in switching between representations, it should cease to be active once participants settle on a given rule in both tasks. If the rlPFC is involved in rule evaluation, its activation should persist in the classification task, but not matching. The results revealed that rlPFC activation persisted into correct trials in classification, but not matching, suggesting that it continues to be involved in the evaluations of evidence for a rule even after participants have arrived at the correct rule.
类别学习是一种关键的神经生物学功能，使生物体能够简化复杂的世界。额侧前皮质（rlPFC）在神经生物学的类别学习研究中经常活跃；然而，该区域在类别学习中的确切作用仍不确定。先前的类别学习研究假设 rlPFC 参与规则之间的切换，而另一些研究则强调规则抽象和评估。我们旨在通过两种常见的类别学习任务：匹配和分类，阐明 rlPFC 在类别学习中的作用，并区分切换和评估解释。匹配任务涉及将参考刺激与四个目标刺激之一匹配。在分类任务中，参与者被呈现单个刺激，并学习将其分类为两个类别之一。匹配和分类是相似的，但对切换和评估的要求不同。在匹配中，规则可以在单次正确答案后确定。在分类中，即使在初始正确响应后，参与者可能仍需要评估规则的证据。这种关键差异允许从切换功能中分离出评估功能。如果 rlPFC 主要参与表示之间的切换，则在两个任务中参与者确定给定规则后，它应该停止活动。如果 rlPFC 参与规则评估，则其在分类任务中的激活应该持续，但在匹配任务中不会。结果表明，在分类中，rlPFC 的激活在正确的试验中持续存在，但在匹配中则不然，这表明即使参与者已经找到了正确的规则，它仍继续参与规则证据的评估。
