Improved control effect of absence seizures by autaptic connections to the subthalamic nucleus

We presently propose a modified basal ganglia-corticothalamic (MBGCT) mean-field network of neural populations by incorporating the autaptic connection to subthalamic nucleus (STN) (termed ACS). The network connection is through the pulse field generated by the incoming pulse rate from the prepopulation, which is functioned into postpopulation. And then, we study the control effect of STN deep brain stimulation (DBS) on epileptic absence seizures characterized by 2-4 Hz spike and wave discharges (SWD) as the modulation of ACS is applied. For the slow dynamical effect of STN on cortical seizure activity, DBS electrodes are employed to generate sustaining input pulse of electrical potential field. In particular, the continuous symmetrical and asymmetrical charge-balanced biphasic pulse DBS with interphase gap, i.e., S-CBBP-IPGx and AS-CBBP-IPGx stimulations, are used due to their less charge and multiply adjustable stimulation parameters, to evaluate their effect on the suppression of SWD occurrence. Based on the percentage of control for the SWD number, it is shown that strong ACS directly contributes to the abatement of SWD. In contrast, weak ACS can significantly improve the control effects of CBBP DBS, which are particularly dependent on the stimulation shapes; i.e., (i) AS-CBBP-IPGx is less beneficial than S-CBBP-IPGx, (ii) CBBP DBS in frequency-dependent manner can bidirectionally modulate the SWD occurrence, and (iii) CBBP DBS with moderate interphase gap (IPG) is more effective to suppress the SWD occurrence than that with no or large IPGs. These results are basically consistent with the experimental findings, which computationally supports the involvement of STN in the control mechanism of epileptic absence seizures.