Department of Cognitive, Linguistic, and Psychological Sciences, USA; University of Pittsburgh, School of Medicine, USA.
Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA.
Cortex. 2023 Mar;160:115-133. doi: 10.1016/j.cortex.2022.09.018. Epub 2023 Feb 1.
The predicted utility of information stored in working memory (WM) is hypothesized to influence the strategic allocation of WM resources. Prior work has shown that when information is prioritized, it is remembered with greater precision relative to other remembered items. However, these paradigms often complicate interpretation of the effects of predicted utility on item fidelity due to a concurrent memory load. Likewise, no fMRI studies have examined whether the predicted utility of an item modulates fidelity in the neural representation of items during the memory delay without a concurrent load. In the current study, we used fMRI to investigate whether predicted utility influences fidelity of WM representations in the brain. Using a generative model multivoxel analysis approach to estimate the quality of remembered representations across predicted utility conditions, we observed that items with greater predicted utility are maintained in memory with greater fidelity, even when they are the only item being maintained. Further, we found that this pattern follows a parametric relationship where more predicted utility corresponded to greater fidelity. These precision differences could not be accounted for based on a redistribution of resources among already-remembered items. Rather, we interpret these results in terms of a gating mechanism that allows for pre-allocation of resources based on predicted value alone. This evidence supports a theoretical distinction between resource allocation that occurs as a result of load and resource pre-allocation that occurs as a result of predicted utility.
工作记忆(WM)中存储的信息的预测效用被假设会影响 WM 资源的策略分配。先前的研究表明,当信息被优先处理时,与其他被记住的项目相比,它的记忆精度更高。然而,由于存在并发的记忆负荷,这些范式通常会使解释预测效用对项目保真度的影响变得复杂。同样,没有 fMRI 研究检查过在没有并发负荷的情况下,项目的预测效用是否会调节记忆延迟期间项目的神经表示的保真度。在当前的研究中,我们使用 fMRI 来研究预测效用是否会影响大脑中 WM 表示的保真度。使用生成模型多体素分析方法来估计在不同预测效用条件下记忆表示的质量,我们观察到具有更高预测效用的项目在记忆中保持更高的保真度,即使它们是唯一要保持的项目。此外,我们发现这种模式遵循一种参数关系,其中更多的预测效用对应于更高的保真度。这些精度差异不能根据已经记住的项目之间的资源重新分配来解释。相反,我们根据单独的预测值来解释这些结果,认为这是一种门控机制,允许根据预测值预先分配资源。这一证据支持了资源分配的理论区别,即资源分配是由于负荷引起的,而资源预先分配是由于预测效用引起的。