Multimodal dissociation of posterior cingulate cortex contributions to episodic memory

项目概要 情景记忆是回忆先前经历细节的能力。研究人员历来依赖 受控项目识别范式，作为自传回忆任务的补充，以研究 情景记忆的生物基质。当代理论认为情景记忆是由 新皮质区域的星座，与海马体和内侧颞叶皮质相一致。其中 在新皮质区域中，后扣带皮层（PCC）脱颖而出，因为它在 对情景记忆的神经影像学研究并证明参与度对记忆强度敏感。 尽管大量文献表明 PCC 对于情景记忆至关重要，但人们对其知之甚少。 在更广泛的记忆或认知中发挥独特的作用。功能性神经影像学研究的荟萃分析 研究了记忆任务和 PCC 激活之间的关系，提供了一些关于该区域的见解 角色。引人注目的是，虽然物品识别任务与 PCC 背侧分区的活动相关 (dPCC)，自传回忆任务与腹侧 PCC 亚区域 (vPCC) 的活动独特相关。 这种功能划分反映了类似的细胞结构和网络连接差异 PCC 的背腹轴。此外，dPCC 始终参与决策研究， 而vPCC被发现参与特定特征和语义的表示 检索到的记忆的关联。综合之前的观察结果表明 dPCC 的作用 作为基于记忆的决策过程中助记证据的假定累加器，而 vPCC 则用于 支持检索有关先前剧集的详细信息。然而，在明确 PCC 的贡献方面取得了进展 由于该区域位于内侧表面内，情景记忆的子区域受到阻碍， 使得使用传统的电生理记录和分离 PCC 信号的动态变得具有挑战性 神经影像学方法。尖端技术的使用可以帮助克服以前的限制 时空精度阻碍了对 PCC 功能的理解：高分辨率 群体和单个神经元活动的功能性神经影像和侵入性电生理记录。 一个公开可用的高分辨率神经影像数据集，每个数据集包含数千个项目识别试验 参与者将用于隔离 PCC 中项目识别响应模式的功能组织。 将分析通过颅内电极收集的人群反应，以便暂时紧密隔离 PCC 上的耦合记忆决策和记忆检索过程。另外，单机录音 来自 PCC 的数据将被收集并用于测试记忆选择性和视觉选择性单元是否可以被 在 PCC 中识别出响应记忆决策而观察到的潜在群体水平信号 检索。这项工作的结果将极大地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衰老和疾病中的进展方式。

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.