Temporally coordinated activity in the primate hippocampus supporting memory formation

项目总结/摘要 海马体在新记忆的形成中起着至关重要的作用;然而，目前还不清楚它是如何形成的。 海马网络对信息进行结构化和处理，为记忆的形成服务。的 海马体的微电路是紧密相连的，它产生了强大的，时间结构的， 活动跨越神经元的集合。微电路图案在特征频率下谐振， 变得活跃，将海马神经元招募到协调的回路中， 局部场电位（LFP）灵长类动物海马LFP表现出复杂的振荡混合物 在记忆任务期间，信号中通常没有主导频率。这是stark 与啮齿动物在探索期间选择性地发生的突出的θ带（6-10 Hz）振荡形成对比 和任务表现，因为动物积极地处理传入的信息。Theta节律活动 啮齿动物海马体由来自内侧隔的输入协调，内侧隔是一条连接通路， 在所有哺乳动物中都有。尽管猴子在大脑中缺乏这种持续的典型θ-波段活动， LFP，跨物种的解剖学保存表明存在一个类似的电路， 灵长类海马体的信息处理在本建议书中，我们将联合收割机与新提供的 电生理技术与创新的计算方法，以量化和模拟复杂的 灵长类LFP的信号。将同时记录整个范围内的单个装置和LFP活动， 海马使用长期植入的超驱动器和线性电极阵列，而猴子执行 虚拟现实中的空间记忆任务此外，我们还将研究内侧隔刺激对 海马振荡动力学和行为。我们将利用新的光谱分析技术 以改善对以瞬态和不规则振荡为特征的LFP的解释。拟议 实验有以下潜在的结果：1）确定海马振荡的关系， 2）开发数据驱动的计算模型， 表征海马振荡的模式，因为它们在时间上和跨海马子域展开 在记忆任务事件期间，以及3）识别内侧隔驱动振荡活动的程度 介导海马体中的主动处理。

Project Summary/Abstract The hippocampus plays a critical role in the formation of new memories; however, it is not clear how information is structured and processed by the hippocampal network in the service of memory formation. The microcircuitry of the hippocampus is richly interconnected, which produces robust, temporally-structured activity spanning ensembles of neurons. Microcircuit motifs resonate at characteristic frequencies when they become active, recruiting hippocampal neurons into coordinated circuits that can be detected in the rhythmicity of local field potentials (LFP). The hippocampal LFP in primates demonstrates a complex mixture of oscillatory signatures, and there is often no dominant frequency in the signal during memory tasks. This stands in stark contrast to the prominent theta band (6-10 Hz) oscillation that occurs in rodents selectively during exploration and task performance as the animal actively processes incoming information. Theta-rhythmic activity in the rodent hippocampus is coordinated by input from the medial septum, which is a connectional pathway that is conserved across all mammals. Although monkeys lack this sustained archetypal theta-band activity in the LFP, the preservation of anatomy across species suggests the presence of a circuit that would similarly govern hippocampal information processing in primates. In this proposal, we will combine newly available electrophysiological technology with innovative computational approaches to quantify and model complex signals of the primate LFP. Single-unit and LFP activity will be simultaneously recorded from the full extent of the hippocampus using chronically-implanted hyperdrives and linear electrode arrays while monkeys perform a spatial memory task in virtual reality. In addition, we will examine the effects of medial septum stimulation on hippocampal oscillatory dynamics and behavior. We will take advantage of novel spectral analysis techniques to improve interpretation of LFPs characterized by transient and irregular oscillations. The proposed experiments have the following potential outcomes: 1) to determine the relationship of hippocampal oscillatory states to neuronal spiking and memory task events, 2) to develop data-driven computational models that characterize patterns in hippocampal oscillations as they unfold in time and across hippocampal subfields during memory task events, and 3) to identify the extent to which the medial septum drives oscillatory activity mediating active processing in the hippocampus.