Hippocampal subfield and medial temporal cortical persistent activity during working memory reflects ongoing encoding.
Hippocampal subfield and medial temporal cortical persistent activity during working memory reflects ongoing encoding.
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DOI：
10.3389/fnsys.2015.00030
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发表时间：
2015
影响因子：
3
通讯作者：
Schon K
中科院分区：
文献类型：
--
作者：
Nauer RK;Whiteman AS;Dunne MF;Stern CE;Schon K
以前的神经成像研究支持内侧颞叶在短暂的工作记忆(WM)延迟期间维持新刺激的作用，并认为延迟期活动预测随后的记忆。此外，切片记录研究还显示内嗅皮层、周边皮质(PRC)和海马区(CA1、CA3、下丘脑)神经元持续尖峰。这些数据导致了计算模型，表明海马区持续的尖峰信号可以维持神经元对感觉信息的表达长达数秒。该机制可以支持WM维护和将信息编码到长期情景记忆中。本研究的目的是使用高分辨率功能磁共振成像来阐明MTL皮质和海马亚区在WM维持中的作用，因为它与后来的情景识别记忆有关。我们对参与者进行扫描，当他们执行延迟匹配以采样任务时，使用新的场景刺激，并在扫描后评估他们对这些场景的记忆。我们假设，持续到延迟期的刺激驱动的激活--一个假定与持续尖峰相关的--将预测稍后的识别记忆。我们的结果表明，海马旁皮质(PHC)、PRC和下丘脑(延伸到DG/CA3和CA1)的采样和延迟期激活与随后记忆强度的增强呈线性相关。这些数据扩展了以前的神经成像研究，通过将这些一起建模为一个连续的正在进行的编码过程，将其分析限制在样本或延迟期，并支持预测持续活动是WM和情景编码的基础的计算框架。
Previous neuroimaging studies support a role for the medial temporal lobes in maintaining novel stimuli over brief working memory (WM) delays, and suggest delay period activity predicts subsequent memory. Additionally, slice recording studies have demonstrated neuronal persistent spiking in entorhinal cortex, perirhinal cortex (PrC), and hippocampus (CA1, CA3, subiculum). These data have led to computational models that suggest persistent spiking in parahippocampal regions could sustain neuronal representations of sensory information over many seconds. This mechanism may support both WM maintenance and encoding of information into long term episodic memory. The goal of the current study was to use high-resolution fMRI to elucidate the contributions of the MTL cortices and hippocampal subfields to WM maintenance as it relates to later episodic recognition memory. We scanned participants while they performed a delayed match to sample task with novel scene stimuli, and assessed their memory for these scenes post-scan. We hypothesized stimulus-driven activation that persists into the delay period—a putative correlate of persistent spiking—would predict later recognition memory. Our results suggest sample and delay period activation in the parahippocampal cortex (PHC), PrC, and subiculum (extending into DG/CA3 and CA1) was linearly related to increases in subsequent memory strength. These data extend previous neuroimaging studies that have constrained their analysis to either the sample or delay period by modeling these together as one continuous ongoing encoding process, and support computational frameworks that predict persistent activity underlies both WM and episodic encoding.