DeDe宝
(2025-05-09 11:47):
#paper doi.org/10.7554/eLife.100287.4, Elife, Stimulus representation in human frontal cortex supports flexible control in working memory. 工作记忆不仅有存储功能,还有指导决策的功能。然而,这些功能通过哪些脑区实现尚无定论。一方面,一些研究认为视觉相关的工作记忆一般在视觉处理相关脑区进行,但一些研究在前额叶同样检测到特定的工作记忆相关的表征。在这个研究中,研究者提出了一个复杂的工作记忆实验,要求被试在低认知需求的复现任务和高认知需求的分类任务之间快速变化,并用fMRI测量整个大脑的活动模式(重点关注早期视觉皮层、顶内沟以及前额叶皮层)。结果表明,相比于低认知需求的任务,在高认知需求的任务中,只有前额叶皮层表现出更强的刺激表征,且强度与被试的表现相关。这说明了前额叶皮层能够随着任务需求和目标的变化灵活地调整其在工作记忆中的作用。
eLife,
2025-4-24.
DOI: 10.7554/eLife.100287.4
Stimulus representation in human frontal cortex supports flexible control in working memory
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Abstract:
When holding visual information temporarily in working memory (WM), the neural representation of the memorandum is distributed across various cortical regions, including visual and frontal cortices. However, the role of stimulus representation in visual and frontal cortices during WM has been controversial. Here, we tested the hypothesis that stimulus representation persists in the frontal cortex to facilitate flexible control demands in WM. During functional MRI, participants flexibly switched between simple WM maintenance of visual stimulus or more complex rule-based categorization of maintained stimulus on a trial-by-trial basis. Our results demonstrated enhanced stimulus representation in the frontal cortex that tracked demands for active WM control and enhanced stimulus representation in the visual cortex that tracked demands for precise WM maintenance. This differential frontal stimulus representation traded off with the newly-generated category representation with varying control demands. Simulation using multi-module recurrent neural networks replicated human neural patterns when stimulus information was preserved for network readout. Altogether, these findings help reconcile the long-standing debate in WM research, and provide empirical and computational evidence that flexible stimulus representation in the frontal cortex during WM serves as a potential neural coding scheme to accommodate the ever-changing environment.
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