Department of Psychology, University of York, Heslington, NY YO10 5DD, United Kingdom.
Department of Psychology, University of Arizona, Tucson, AZ 85719, United States.
Cereb Cortex. 2022 Dec 15;33(1):152-166. doi: 10.1093/cercor/bhac058.
How concepts are coded in the brain is a core issue in cognitive neuroscience. Studies have focused on how individual concepts are processed, but the way in which conceptual representation changes to suit the context is unclear. We parametrically manipulated the association strength between words, presented in pairs one word at a time using a slow event-related fMRI design. We combined representational similarity analysis and computational linguistics to probe the neurocomputational content of these trials. Individual word meaning was maintained in supramarginal gyrus (associated with verbal short-term memory) when items were judged to be unrelated, but not when a linking context was retrieved. Context-dependent meaning was instead represented in left lateral prefrontal gyrus (associated with controlled retrieval), angular gyrus, and ventral temporal lobe (regions associated with integrative aspects of memory). Analyses of informational connectivity, examining the similarity of activation patterns across trials between sites, showed that control network regions had more similar multivariate responses across trials when association strength was weak, reflecting a common controlled retrieval state when the task required more unusual associations. These findings indicate that semantic control and representational sites amplify contextually relevant meanings in trials judged to be related.
概念在大脑中是如何编码的是认知神经科学的核心问题。研究集中在如何处理单个概念，但概念表示如何适应上下文的变化尚不清楚。我们使用慢事件相关 fMRI 设计，参数化地操纵了单词之间的关联强度，一次呈现一对单词。我们结合了表示相似性分析和计算语言学来探究这些试验的神经计算内容。当项目被判断为不相关时，单个单词的含义保持在缘上回（与言语短期记忆相关），而当检索到链接上下文时则不是。相反，上下文相关的含义则由左外侧前额叶（与控制检索相关）、角回和腹侧颞叶（与记忆的综合方面相关）表示。信息连通性分析检查了站点之间试验中激活模式的相似性，结果表明，当关联强度较弱时，控制网络区域在试验中具有更相似的多元响应，反映了当任务需要更不寻常的关联时，共同的控制检索状态。这些发现表明，语义控制和表示站点在被判断为相关的试验中放大了与上下文相关的含义。
