Optimization of stimulation waveforms for regulating spike-wave discharges in a thalamocortical model

Based on our modified thalamocortical model considering excitatory interneuron, this study incorporates deep brain stimulation (DBS) applied to pyramidal cluster and focuses on optimizing stimulus waveforms of DBS. The epileptic activities can be reproduced and modulated by inhibitory and excitatory interneurons, which are closely related to the generation of absence seizures. Under the bifurcation mechanism analysis, fold limit cycle and Hopf bifurcations well explain the termination and transition of various discharge states. To offer a potential way to improve control effects and energy savings, we investigate a range of waveforms covering rectangular, linear increase and decrease, triangular, exponential increase and decrease, Gaussian and sinusoidal pulse in detail. These single pulses all can effectively remove spike-wave discharges (SWD) with appropriate stimulus parameters, except for exponential decrease pulse. Additionally, stimulation outcomes are uncovered by adjusting stimulus timing and pulse width, and the optimal pulse width of each waveform has been suggested. By comprehensively analyzing the control rate, charge injected ability and energy requirement, the sinusoidal pulse achieves a better impact on eliminating SWD. From the perspective of rectangular and sinusoidal stimulations, the single pulse is of great advantage comparing to the traditional DBS, which may give some enlightenment for the clinical treatment, especially extend the application of DBS in neurological disorders.