Olson Jared D, Wander Jeremiah D, Johnson Lise, Sarma Devapratim, Weaver Kurt, Novotny Edward J, Ojemann Jeffrey G, Darvas Felix
University of Washington, Department of Rehabilitation Medicine, USA; University of Washington, Center for Sensorimotor Neural Engineering, USA.
University of Washington, Center for Sensorimotor Neural Engineering, USA; University of Washington, Department of Bioengineering, USA.
Clin Neurophysiol. 2016 Jan;127(1):277-284. doi: 10.1016/j.clinph.2015.03.014. Epub 2015 Apr 9.
The purpose of this study is to determine the relationship between cortical electrophysiological (CE) signals recorded from the surface of the brain (subdural electrocorticography, or ECoG) and signals recorded extracranially from the subgaleal (SG) space.
We simultaneously recorded several hours of continuous ECoG and SG signals from 3 human pediatric subjects, and compared power spectra of signals between a differential SG montage and several differential ECoG montages to determine the nature of the transfer function between them.
We demonstrate the presence of CE signals in the SG montage in the high-gamma range (HG, 70-110 Hz), and the transfer function between 70 and 110 Hz is best characterized as a linear function of frequency. We also test an alternative transfer function, i.e. a single pole filter, to test the hypothesis of frequency dependent attenuation in that range, but find this model to be inferior to the linear model.
Our findings indicate that SG electrodes are capable of recording HG signals without frequency distortion compared with ECoG electrodes.
HG signals could be recorded minimally invasively from outside the skull, which could be important for clinical care or brain-computer interface applications.
本研究旨在确定从大脑表面记录的皮层电生理（CE）信号（硬膜下皮层脑电图，即ECoG）与从帽状腱膜下（SG）间隙颅外记录的信号之间的关系。
我们同时记录了3名儿科受试者数小时的连续ECoG和SG信号，并比较了差分SG导联与几个差分ECoG导联之间信号的功率谱，以确定它们之间传递函数的性质。
我们证明了在SG导联中存在高伽马范围（HG，70 - 110 Hz）的CE信号，并且70至110 Hz之间的传递函数最适合表征为频率的线性函数。我们还测试了另一种传递函数，即单极滤波器，以检验该范围内频率依赖性衰减的假设，但发现该模型不如线性模型。
我们的研究结果表明，与ECoG电极相比，SG电极能够在不产生频率失真的情况下记录HG信号。
HG信号可以通过微创方式从颅骨外记录，这对于临床护理或脑机接口应用可能很重要。
