Mapping Human Memory with Electrocorticography & Chronometric Stimulation

描述（由申请人提供）：这个项目的目标是确定低频振荡是否作为协调人类情景记忆的皮层区域的机制。为了解决这个问题，我们将首先在患者中使用创新的多小叶皮质电图（ECOG）记录来确定情景记忆的相互关联的大脑区域集，之前的研究和我们的初步工作强烈建议包括内侧颞叶，前额叶皮层和顶叶皮层。然后，我们将对同一患者的高连接区域（中枢）进行时序刺激，包括同时记录和刺激两个不同的大脑区域。计时刺激是有利的，因为它涉及到的刺激模仿了另一个大脑区域正在进行的记录活动的频率和幅度，潜在地减少了不必要的刺激传播到其他大脑区域，同时提供了对神经通信实际发生方式的洞察。采用这种方法，我们将采用两种不同的刺激方法，同相或非同相刺激，并在连接集线器中持续记录振荡。这将使我们能够确定：1)具有高度连通性的区域（“中枢”）是否对情景记忆是必要的；2)同相连贯振荡是否可以增强情景记忆检索；3)非同相振荡是否会导致记忆性能下降。我们在这里的方法结合了创新的工具，如皮质电图术和人体时间刺激，以及涉及图论的分析技术。反过来，这些将使我们进一步了解大脑区域网络如何以及以何种方式相互作用，作为它们在情景记忆中的作用的一部分。这项工作与临床研究相关，因为它可以深入了解其他大脑区域在中风相关的内侧颞叶损伤后补偿功能丧失的程度，内侧颞叶是情景记忆的“中枢”。它还将促进我们对设计和实施深部脑刺激器治疗伴随神经疾病的认知障碍的潜在方法的理解。例如，如果这里概述的实验是成功的，它们将意味着将刺激时间与远端记录的振荡活动同步的设备可以恢复甚至增强患有神经疾病的患者受损的记忆功能。

DESCRIPTION (provided by applicant): The goal of this project is to determine whether low frequency oscillations serve as a mechanism for coordinating cortical areas underlying human episodic memory. To address this issue, we will first employ innovative multilobular electrocortigraphic (ECOG) recordings in patients to determine the sets of interconnected brain areas underlying episodic memory, which previous research and our preliminary work strongly suggest to include the medial temporal lobes, prefrontal cortex, and parietal cortex. We will then perturb areas of high connectivity (hubs) in the same patients using chronometric stimulation, which involves simultaneous recording and stimulation from two different brain regions. Chronometric stimulation is advantageous because it involves stimulation that mimics the frequency and amplitude of on-going recorded activity in another brain region, potentially mitigating unwanted spread of stimulation to other brain areas and at the same time providing insight into how neural communication might actually occur. We will employ two different stimulation methods with this approach, either in phase or out of phase stimulation with the on-going recorded oscillations in connecting hubs. This will allow us to determine whether 1) areas with high degrees of connectivity ("hubs") are necessary for episodic memory 2) whether in- phase, coherent oscillatory can enhance episodic memory retrieval 3) whether out-of- phase oscillations result in decrements in memory performance. Our approach here combines innovative tools, such as electrocorticography and chronometric stimulation in humans and analysis techniques involving graph theory. These in turn will allow us to advance our understanding of how and in what manner networks of brain regions interact as part of their role in episodic memory. This work is relevant to clinical research because it can provide insight into the extent to which other brain regions can compensate for lost function following stroke-related lesions to the medial temporal lobes, a known "hub" in episodic memory. It will also advance our understanding of potential ways to design and implement deep brain stimulators to treat cognitive impairments accompanying neural disease. For example, if the experiments outlined here are successful, they would imply that devices that time stimulation to be in-phase with distant recorded oscillatory activity could restore or even enhance impaired memory function in patients suffering from neural disease.