INSERM U1099, LTSI, Campus de Beaulieu, 35042 Rennes Cedex, France; Université de Rennes 1, LTSI, Campus de Beaulieu, 35042 Rennes Cedex, France; AZM Center-EDST, Lebanese University, El mitein Street, 1300 Tripoli, Lebanon.
INSERM U1099, LTSI, Campus de Beaulieu, 35042 Rennes Cedex, France; Université de Rennes 1, LTSI, Campus de Beaulieu, 35042 Rennes Cedex, France.
Clin Neurophysiol. 2018 Apr;129(4):829-841. doi: 10.1016/j.clinph.2018.01.062. Epub 2018 Feb 11.
In this study we aim to identify the key (patho)physiological mechanisms and biophysical factors which impact the observability and spectral features of High Frequency Oscillations (HFOs).
In order to accurately replicate HFOs we developed virtual-brain/virtual-electrode simulation environment combining novel neurophysiological models of neuronal populations with biophysical models for the source/sensor relationship. Both (patho)physiological mechanisms (synaptic transmission, depolarizing GABA effect, hyperexcitability) and physical factors (geometry of extended cortical sources, size and position of electrodes) were taken into account. Simulated HFOs were compared to real HFOs extracted from intracerebral recordings of 2 patients.
Our results revealed that HFO pathological activity is being generated by feed-forward activation of cortical interneurons that produce fast depolarizing GABAergic post-synaptic potentials (PSPs) onto pyramidal cells. Out of phase patterns of depolarizing GABAergic PSPs explained the shape, entropy and spatiotemporal features of real human HFOs.
The terminology "high-frequency oscillation" (HFO) might be misleading as the fast ripple component (200-600 Hz) is more likely a "high-frequency activity" (HFA), the origin of which is independent from any oscillatory process.
New insights regarding the origins and observability of HFOs along depth-EEG electrodes were gained in terms of spatial extent and 3D geometry of neuronal sources.
本研究旨在确定影响高频振荡（HFO）可观测性和光谱特征的关键（病理）生理机制和生物物理因素。
为了准确复制 HFO，我们开发了一个虚拟大脑/虚拟电极模拟环境，将神经元群体的新型神经生理学模型与源/传感器关系的生物物理模型相结合。（病理）生理机制（突触传递、去极化 GABA 效应、超兴奋性）和物理因素（扩展皮质源的几何形状、电极的大小和位置）都被考虑在内。模拟 HFO 与从 2 名患者的颅内记录中提取的真实 HFO 进行了比较。
我们的结果表明，HFO 病理性活动是由皮质中间神经元的前馈激活产生的，这些中间神经元对锥体神经元产生快速去极化 GABA 能突触后电位（PSPs）。去极化 GABA 能 PSP 的异相模式解释了真实人类 HFO 的形状、熵和时空特征。
术语“高频振荡”（HFO）可能具有误导性，因为快速波纹成分（200-600 Hz）更可能是“高频活动”（HFA），其起源与任何振荡过程无关。
在空间范围和神经元源的 3D 几何形状方面，关于 HFO 的起源和可观测性的新见解在深度 EEG 电极方面得到了深入了解。
