title: A decrease of ripples precedes seizure onset in mesial temporal lobe epilepsy.
abstract: High-frequency oscillations (HFOs) are promising biomarkers for epileptic foci; however, their characteristic changes during the preictal period remain unclear. Here, the preictal HFOs were recorded and detected by an automated HFOs detection method in the mouse pilocarpine model as well as in patients with mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy. A total of sixteen low-voltage fast (LVF) and fifty-three hypersynchronous-onset (HYP) seizures were recorded in ten mice. The rate of ripples (80-250Hz) decreased during 1min before the onset of LVF and HYP seizures, which was primarily due to the reduction of type II (independent of epileptiform discharges) rather than type I ripples (superimposed on epileptiform activities). The ripple rate decreased until 30s before HYP seizure, whereas it increased with a peak at 40s during the 1min preictal period of LVF seizures. Furthermore, the "ripple reduction" phenomenon was also observed in all twelve seizures from nine patients with mTLE but not in neocortical epilepsy. These results indicate that ripples may potentially be helpful for understanding the mechanisms of ictogenesis in mTLE, and the different modes of ripple changes during the minute before LVF and HYP seizures might also be beneficial for the diagnosis of seizure types.
authors.affiliation: Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Cenglin
authors.initials: C
authors.lastname: Xu
authors.affiliation: Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Computer Science, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Kang
authors.initials: K
authors.lastname: Lin
authors.affiliation: Department of Computer Science, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Pan
authors.affiliation: Laboratory of Brain Function and Disease in Chinese Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.
authors.forename: Zhenghao
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Jorge
authors.initials: J
authors.lastname: Gonzalez-Martinez
authors.affiliation: Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.affiliation: Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Shihong
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Bulacio
authors.affiliation: Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Imad M
authors.initials: IM
authors.lastname: Najm
authors.affiliation: Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Jianhong
authors.initials: J
authors.lastname: Luo
authors.affiliation: Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Hu
authors.affiliation: Department of Computer Science, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Norman K
authors.initials: NK
authors.lastname: So
authors.affiliation: Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Medicine, Zhejiang University, Hangzhou, China; Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China. Electronic address: chenzhong@zju.edu.cn.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Chen
keywords: High frequency oscillations; Mesial temporal lobe epilepsy; Preictal