Robust closed-loop control of spike-and-wave discharges in a thalamocortical computational model of absence epilepsy

Abstract

In this paper, we investigate the abatement of spike-and-wave discharges in a thalamocortical model using a closed-loop brain stimulation method. We first explore the complex states and various transitions in the thalamocortical computational model of absence epilepsy by using bifurcation analysis. We demonstrate that the Hopf and double cycle bifurcations are the key dynamical mechanisms of the experimental observed bidirectional communications during absence seizures through top-down cortical excitation and thalamic feedforward inhibition. Then, we formulate the abatement of epileptic seizures to a closed-loop tracking control problem. Finally, we propose a neural network based sliding mode feedback control system to drive the dynamics of pathological cortical area to track the desired normal background activities. The control system is robust to uncertainties and disturbances, and its stability is guaranteed by Lyapunov stability theorem. Our results suggest that the seizure abatement can be modeled as a tracking control problem and solved by a robust closed-loop control method, which provides a promising brain stimulation strategy.

A Closed-Loop Brain Stimulation Control System Design Based on Brain-Machine Interface for Epilepsy

“…Since it is unreliable to utilize open-loop brain neural stimulation to eliminate the pathological spike-and-wave discharges in the absence of epilepsy seizures, it is required to seek a more comprehensive closed-loop stable control scheme. However, epilepsy seizure abatement based on the closed-loop control system has not been studied very well and the existing results are very few [11,20].…”

“…erefore, this paper focuses on a closed-loop control strategy for epilepsy seizure abatement based on DBS [18][19][20], which can adjust the stimulus signal in real time by the controller in the computer. Certainly, the connection between the brain and the computer can be wireless, as shown in Figure 2, or wired as Figure 3.…”

“…Considering extensive nonlinear term owing to uncertainties in cerebral blood flow, glucose metabolism, blood oxygen level dependence (BOLD), and electromagnetic disturbances, which may affect network connectivity and neural electrical signal, the interaction within the thalamocortical system of epilepsy is modeled by the following differential equations [20]: Complexity…”

“…In some investigations, it has been shown that long-term service of epilepsy drugs may lead to liver decline or even damage due to epilepsy is a long-term chronic disease [17,18]. On the contrary, neurosurgical resection of the epileptic area cannot be applied to patients with systemic epilepsy [19,20]. erefore, it urgently needs an alternative method for absence epilepsy to solve the above problems due to limitations of the abovementioned drugs and surgical treatment [17][18][19][20].…”

“…Considering the high nonlinearity, unmodeled dynamics, and ubiquitous disturbance in the nervous system, seizure oscillations, noise, and disturbance changes are not accurate; therefore, the method in [33] cannot deal with epilepsy seizures very well [34,35]. Based on the abovementioned problems, Ge proposed a robust closed-loop control which adapts to high nonlinearity, unmodeled dynamics, and ubiquitous disturbance of the nervous system and has stable control for seizures [20], but a slow convergence rate is its biggest drawback. e finite time sliding mode control technique can accelerate system convergence and is an effective strategy for nonlinear systems with high nonlinearity, unmodeled dynamics, and unknown disturbances [36][37][38][39].…”