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Interactions between hippocampus, prefrontal cortex and visual association cortex during short-term memory maintenance

短期记忆维持过程中海马体、前额叶皮层和视觉关联皮层之间的相互作用

基本信息

批准号：
255020759
负责人：
Professor Dr. Nikolai Axmacher
金额：
--
依托单位：
Abteilung Neuropsychologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/255020759?language=en
关键词：
Interactions between hippocampus prefrontal cortex

项目摘要

Visual short-term memory (STM) refers to the maintenance of visual information for a short time interval. Key brain regions of visual STM include the prefrontal cortex and parietooccipital regions. Furthermore, increasing evidence suggests that the hippocampus is recruited when multiple items need to be maintained; however, it is still unclear if and how STM-related mechanisms in hippocampus, prefrontal cortex and parietooccipital regions are interrelated. Maintenance of specific items can be investigated by multivariate pattern classification analyses (MVPA) which can be applied to both EEG and fMRI data. However, no previous study has investigated stimulus-specific reactivation of multiple items during STM. Furthermore, it is unknown if and how hippocampus and prefrontal cortex interact with regions supporting stimulus-specific representations, and if they control these representations. Here, we will address these open questions. According to an influential computer model, STM depends on a multiplexing buffer in which items are consecutively reactivated during subsequent phase ranges of neural oscillations in the theta (3-8 Hz) frequency range. Specifically, we will thus test the hypothesis that hippocampus and/or prefrontal cortex control representations of specific items via oscillatory interactions with distributed activity patterns in visual association areas. We will investigate two groups of participants: Presurgical epilepsy patients who are implanted with hippocampal and/or neocortical intracranial EEG (iEEG) electrodes for planning of resective surgery, and healthy participants undergoing simultaneous EEG/fMRI. Stimulus-specific representations will be assessed using MVPA on iEEG data (in the iEEG experiment) and on scalp EEG data (in the simultaneous EEG/fMRI experiment). Simultaneously, hippocampal activation will be analyzed using either iEEG from the hippocampus or fMRI recordings in the healthy participants. This project will help clarifying the neural mechanisms underlying visual STM and the role of the hippocampus for multi-item STM.

视觉短时记忆是指视觉信息在短时间内的保持。视觉短时记忆的关键脑区包括前额叶皮层和顶枕区。此外，越来越多的证据表明，当需要维持多个项目时，海马会被招募;然而，海马、前额叶皮层和顶枕区的STM相关机制是否以及如何相互关联仍不清楚。特定项目的维护可以通过多变量模式分类分析（MVPA）进行研究，该分析可以应用于EEG和fMRI数据。然而，没有以前的研究已经调查的刺激特定的多个项目在STM的再激活。此外，海马体和前额叶皮层是否以及如何与支持刺激特异性表征的区域相互作用，以及它们是否控制这些表征，都是未知的。在这里，我们将讨论这些开放的问题。根据一个有影响力的计算机模型，STM依赖于一个多路复用缓冲器，在该缓冲器中，项目在theta（3-8 Hz）频率范围内的神经振荡的后续相位范围内被连续地重新激活。具体来说，我们将因此测试的假设，海马和/或前额叶皮层控制的特定项目通过振荡的相互作用与分布在视觉关联领域的活动模式的代表。我们将调查两组参与者：植入海马和/或新皮层颅内EEG（iEEG）电极用于计划切除手术的术前癫痫患者，以及同时进行EEG/fMRI的健康参与者。将使用MVPA对iEEG数据（在iEEG实验中）和头皮EEG数据（在同步EEG/fMRI实验中）评估刺激特异性表征。同时，将使用来自海马的iEEG或健康参与者的fMRI记录来分析海马激活。本研究将有助于阐明视觉短时记忆的神经机制和海马在多项目短时记忆中的作用。