Realistic Measurements of tDCS-Modulated Activity and Electric Fields in the Human Brain In Vivo

本项目的重点是用神经工程学的方法来改进非侵入性康复策略。 脑刺激(NIBS)技术称为经颅直流电刺激(Tdcs)。Tdcs正在 在各种神经精神疾病的康复过程中进行了大量调查，包括抑郁症和中风。 然而，tdcs在不同受试者之间并不表现出一致的疗效，这可以归因于个体之间的差异。 由不同强度的电场(EF)和由此引起的神经活动变化引起的可变性。是这样的 如果根据tdcs生成的EF和tdcs-1滴定tdcs治疗剂量，则可以减少恢复中的变异性。 调节神经活动。像头皮脑电(EEG)这样的非侵入性方法使用方便 不涉及侵入性的颅内记录程序，例如皮层脑电图术(ECoG)和/或 立体脑成像(SEEG)。然而，与之相比，脑电的时空分辨率是次优的。 ECoG/SEEG，可能是因为容量传导。因此，一个可以实现的传递函数 使用脑电记录的ECOG/SEEG级别的精度是可取的。为此，该项目将建立一个 同时记录EEG、ECoG和/或SEEG以及tDCS应用的框架。这样的一个 框架将产生一个传递函数，该传递函数对于基于tdcs剂量个体化的研究可能非常有用。 使用非侵入性方法(例如脑电波)研究神经活动。这样的方法在以下情况下可能更可靠 与基于仿真模型的方法相比。难治性癫痫患者的ECoG/SEEG检查 植入作为研究神经系统对tdcs反应的实时反应的自然模型。 本项目中要调查的两个重叠区域是： 1.基于脑电的tDCS产生的EF的外推能否达到与ECoG/SEEG相当的精度- 基于外推的吗？与EEG相比，ECOG/SEEG具有更好的时空分辨率，但 侵入性的，因此在中风患者中不实用。通过对两种脑电同时记录的分析 和ECoG/SEEG在受试者中，将开发新的算法来使用EEG外推tDCS产生的EF 这可以与ECoG/SEEG外推的准确性相匹配。 2.头皮EEG与侵袭性ECoG/SEEG在应用tdcs前、中、后的相关性有多大？ 了解tdcs与神经活动的直接相互作用的第一步是同时给药。 并记录不同深度的神经活动。要实现这一点，需要专门的录音设置 我们计划使用临床设置进行一些修改，以确保患者的安全。专门的软件是 在tdcs给药期间需要处理数据以准确定位神经活动的来源， 比较了基于EEG和基于ECoG/SEEG的声源定位方法。 从长远来看，我们的多学科团队有信心提供一种新颖的、非侵入性的基于神经反馈的 神经调节方法的tdcs剂量个体化，以达到有效的恢复结果。

This project focuses on a neuroengineering approach to improve rehabilitative strategies involving non-invasive brain stimulation (NIBS) technique called transcranial direct current stimulation (tDCS). tDCS is being investigated heavily in recovery from a variety of neuropsychiatric conditions, including depression and stroke. However, tDCS does not show consistent efficacy across subjects, which can be attributed to inter-individual variability resulting from different strength of electric fields (EF) and resultant changes in neural activity. Such variability in recovery can be decreased if tDCS therapy dose is titrated based on tDCS-generated EF and tDCS- modulated neural activity. Non-invasive methods like scalp electroencephalography (EEG) are convenient to use without involving invasive intracranial recording procedures, e.g., electrocorticography (ECoG) and/or stereoencephalography (SEEG). However, the spatiotemporal resolution of EEG is suboptimal when compared with ECoG/SEEG, probably because of volume conduction. Therefore, a transfer function that can achieve ECoG/SEEG-level precision using EEG recordings is desirable. To that end, this project will establish a framework of simultaneous recording of EEG, ECoG and/or SEEG along with tDCS application. Such a framework will yield a transfer function that may be very useful to investigate tDCS dose-individualization based on neural activity using non-invasive methods (e.g., EEG). Such an approach may be more reliable when compared to a simulation model-based approach. Subjects with refractory epilepsy undergoing ECoG/SEEG implantation serve as a natural model to investigate the real-time reactivity of neural system in response to tDCS. The two overlapping areas to be investigated in this project are: 1. Can EEG-based extrapolations of tDCS-generated EF achieve accuracy comparable to ECoG/SEEG- based extrapolations? ECoG/SEEG have superior spatiotemporal resolution compared to EEG, but are invasive and therefore not practical in stroke subjects. Through analyzing simultaneous recording of both EEG and ECoG/SEEG in subjects, new algorithms will be developed to extrapolate tDCS-generated EF using EEG that can match the accuracy of ECoG/SEEG extrapolations. 2. How tightly correlated are scalp EEG and invasive ECoG/SEEG before/during/after tDCS application? The first step towards understanding direct interaction of tDCS with neural activity is simultaneous administration of tDCS and recording neural activity at various depths. Specialized recording setup is required to achieve this and we plan to use clinical setup with some modifications, ensuring patient safety. Specialized software is required to process the data towards accurate source localization of neural activity during tDCS administration, and to compare EEG-based source localization with the ECoG/SEEG-based. In the long term, our multidisciplinary team is confident to deliver a novel, non-invasive neural feedback-based, neuromodulatory approach to tDCS dose-individualization towards efficacious recovery outcomes.