Multimodal dissociation of posterior cingulate cortex contributions to episodic memory

项目摘要 情节记忆是回忆以前经历的细节的能力。研究人员历来依赖于 受控项目再认范式，作为自传体回忆任务的补充，以考察 情景记忆的生物基础。当代理论认为，情节记忆由一种 新皮质区域的星座，与海马体和内侧颞叶皮质一致。其中 在新皮质区域，后扣带回皮质(PCC)特别突出，因为它在 对情景记忆的神经成像研究表明，参与对记忆强度很敏感。 尽管大量文献表明PCC对情景记忆至关重要，但人们对其知之甚少 在更广泛的记忆或认知中的独特作用。对功能神经成像研究的荟萃分析 研究了记忆任务和PCC激活之间的关系，为该地区的 角色。值得注意的是，尽管项目识别任务与PCC背侧亚区的活动有关 (DPCC)，自传性回忆任务与腹侧PCC亚区(VPCC)的活动唯一相关。 这种功能划分反映了在 PCC的背腹轴。此外，DPCC一直牵涉到决策研究中， 而vPCC被发现参与了特定特征和语义的表征 检索到的记忆的关联。综合以前的观察结果表明，DPCC服务于 在基于记忆的决策过程中作为助记证据的假定累加器，而vPCC则起到 支持检索之前剧集的详细信息。然而，在澄清PCC的贡献方面取得了进展 情节记忆的子区域由于该区域在内侧表面内的位置而受到阻碍， 这使得使用传统的电生理记录和分离PCC信号的动力学变得具有挑战性 神经成像方法。尖端技术的使用可以帮助克服以前在 阻碍对PCC功能理解取得进展的时空精度：高分辨率 功能神经成像和侵入性电生理记录群体和单个神经元的活动。 一个开放的、高分辨率的神经成像数据集，每个数据集包含数千个项目识别试验 Participant将被用来隔离PCC中项目识别反应模式的功能组织。 通过颅内电极收集的群体反应将被分析，以便在时间上紧密隔离 整个PCC的记忆-决策和记忆-检索过程相互耦合。此外，单单元录制 将收集并用于测试记忆选择单元和视觉选择单元是否可以 在PCC中识别的、响应于存储器决策而观察到的潜在种群水平信号以及 取回。这项工作的结果将大大促进我们对职能组织的理解 在PCC中，帮助绘制记忆缺陷在健康老龄化和疾病中发展的方式。

Project Summary Episodic memory is the ability to recall details about prior experiences. Researchers have historically relied on controlled item-recognition paradigms, in complement to autobiographical recall tasks, to investigate the biological substrates of episodic memory. Contemporary theories posit that episodic memory is supported by a constellation of neocortical regions, in concert with the hippocampus and medial temporal cortices. Of these neocortical regions, the posterior cingulate cortex (PCC) stands out because it is reliably observed in neuroimaging studies of episodic memory and demonstrates engagement that is sensitive to memory strength. Although a large literature indicates that the PCC is critical for episodic memory, very little is known about its unique role in memory or cognition more broadly. Meta-analyses of functional neuroimaging studies that have investigated the relationship between memory tasks and PCC activations provide some insight as to the region’s role. Strikingly, while item-recognition tasks are associated with activity in the dorsal subregion of the PCC (dPCC), autobiographic recall tasks are uniquely associated with activity in the ventral PCC subregion (vPCC). This functional divide mirrors similar cytoarchitectural and network-connectivity differences found along the dorsal-ventral axis of the PCC. Furthermore, the dPCC is consistently implicated in decision-making studies, while the vPCC has been found to be involved in the representation of specific features and semantic associations of retrieved memories. Synthesizing across previous observations suggests that the dPCC serves as a putative accumulator of mnemonic evidence during memory-based decisions, while the vPCC serves to support the retrieval of details about previous episodes. However, progress in clarifying the contributions of PCC subregions to episodic memory have been stymied due to the location of the region within the medial surface, making it challenging to isolate the dynamics of PCC signals using traditional electrophysiological recording and neuroimaging methods. The use of cutting-edge techniques can help overcome previous limitations in spatiotemporal precision that have prevented advances in understanding the function of the PCC: high-resolution functional neuroimaging and invasive electrophysiological recordings of population and single neuron activity. An openly-available, high-resolution neuroimaging dataset containing thousands of item-recognition trials per participant will be used to isolate the functional organization of item-recognition response patterns in the PCC. Population responses collected via intracranial electrodes will be analyzed in order to temporally isolate tightly coupled memory-decision and memory-retrieval processes across the PCC. Additionally, single unit recordings from the PCC will be collected and used to test whether memory-selective and visual-selective units can be identified in the PCC, underlying population level signals observed in response to memory decisions and retrieval. Results from this work will provide a significant advance to our understanding of functional organization in the PCC, helping map the ways memory deficits can progress in healthy aging and disease.