Title:：Large-scale Brain Dynamical Mechanisms for Absence Seizures 

Speaker： Dr. Dong-Ping Yang, University of Sydney, Australia 

Chair： Prof. Shan Yu, Brainnetome Center, CASIA 

Time： 09:30-10:30, Dec. 24, 2018 

Venue：The 3rd meeting room, 3rd floor, Intelligence Building 

Abstract:

Absence epilepsy is characterized by a sudden paroxysmal loss of consciousness accompanied by oscillatory activity propagating over many brain areas. A physiologically based corticothalamic model of large-scale brain activity is used to analyze critical dynamics of transitions from normal arousal states to epileptic seizures, which correspond to Hopf bifurcations. This relates an abstract normal form quantitatively to the main underlying physiologies that includes neural dynamics, axonal propagation, and time delays. Thus, a bridge is constructed that enables normal forms to be used to interpret quantitative data. This model is further investigated with focal spatial heterogeneity, numerically and analytically. An emergent spatiotemporal dynamic is found for seizure localization, whose spatiotemporal properties are comparable with experimental observations, providing a new biophysical explanation of the temporally higher frequency, but spatially more localized cortical waves observed in genetic rodents that display characteristics of human absence epilepsy, from the perspective of large-scale brain dynamics. Predictions are also presented for further experimental test. Thus, we propose a dynamical mechanism to unify the global and focal aspects of absence epilepsy with focal absence seizures associated with seizure localization, and the global ones associated with seizure generalization. We are seeking more real data to compare with the model, and to decide whether and how to add more details of cellular nonlinear dynamics or heterogeneous connectivity into the large-scale brain dynamics. 

Biography:

杨冬平博士目前在悉尼大学物理系复杂系统研究组做博士后。2011年毕业于厦门大学，获得生物物理博士学位。博士期间致力于复杂网络和博弈共演化动力学以及细胞内钙离子通道的生物建模。之后前往香港浸会大学周昌松组里做博士后，开始转向研究计算神经科学，利用计算机模拟和理论分析发现脑皮层活动的多尺度性质在信息容量的成本－效益原理框架下可以很好地组织起来 。他专长于生物建模，数值模拟，和理论分析，特别是复杂系统和非线性理论。目前利用计算模拟和非线性动力学理论分析来理解大脑系统中临界动力学的时空特点以及探寻潜在的预警信号，例如大脑清醒到睡眠的转变过程及其潜在的预警信号，正常状态到癫痫状态的不同转变类型，以及癫痫的扩散过程。