Ozaki Isamu, Hashimoto Isao
Faculty of Health Sciences, Aomori University of Health and Welfare, Aomori, Japan.
Clin EEG Neurosci. 2005 Oct;36(4):271-7. doi: 10.1177/155005940503600406.
A brief review of previous studies is presented on ultra-fast activities > 300 Hz (high frequency oscillations, HFOs) overlying the cortical response in the somatosensory evoked potential (SEP) or magnetic field (SEF). The characteristics of somatosensory HFOs are described in terms of reproducibility and origin (area 3b and 1) of the HFOs, changes during a wake-sleep cycle, effects of higher stimulus rate or tactile interference, etc. Also, several hypotheses on the neural mechanisms of the HFOs are introduced; the early HFO burst is probably generated from action potentials of thalamocortical fibers at the time when they arrive at the area 3b (and 1), since this component is resistant to higher stimulus rate > 10Hz or general anesthesia: by contrast, the late HFO burst is sensitive to higher stimulus rate, reflecting activities of a postsynaptic neural network in the somatosensory cortices, area 3b and 1. As to possible mechanisms of the late HFO burst genesis, an interneuron hypothesis, a fast inhibitory postsynaptic potential (IPSP) hypothesis of the pyramidal cell and a chattering cell hypothesis will be discussed on the basis of physiological and pathological features of the somatosensory HFOs.
本文简要回顾了先前关于体感诱发电位（SEP）或磁场（SEF）中皮质反应之上超过300Hz的超快活动（高频振荡，HFOs）的研究。体感HFOs的特征从其可重复性和起源（HFOs的3b区和1区）、觉醒-睡眠周期中的变化、更高刺激率或触觉干扰的影响等方面进行了描述。此外，还介绍了关于HFOs神经机制的几种假说；早期HFO爆发可能是丘脑皮质纤维到达3b区（和1区）时其动作电位产生的，因为该成分对高于10Hz的更高刺激率或全身麻醉具有抗性：相比之下，晚期HFO爆发对更高刺激率敏感，反映了体感皮层3b区和1区突触后神经网络的活动。关于晚期HFO爆发产生的可能机制，将根据体感HFOs的生理和病理特征讨论中间神经元假说、锥体细胞的快速抑制性突触后电位（IPSP）假说和喋喋不休细胞假说。
