Control of absence seizures by the combination effects of the SNr-TRN and SNr-SRN pathways.

<p>A, B: The state analysis (A) and frequency analysis (B) in the () panel. Here is the scale factor, and is the excitatory coupling strength of the STN-SNr pathway. Unlike previous results, only three dynamical state regions are observed in the phase diagram (A): the SWD oscillation region (II), the simple oscillation region (III) and the low firing region (IV), corresponding to the dynamical states defined in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003495#pcbi-1003495-g002" target="_blank">Fig. 2</a>(D). For relatively weaker scale factor , both increase and decrease in the activation level of SNr can inhibit the SWDs (double arrow, bidirectional suppression); whereas for sufficiently strong , only reducing the activation level of SNr suppresses the SWDs (single arrow, unidirectional suppression). In (A), the white dashed line represents the boundary of suppression region, and the red dashed line stands for the demarcation between the bidirectional and unidirectional suppression regions. The yellow asterisk region surrounded by black dashed lines in (B) denotes the SWD oscillation region that falls into the 2–4 Hz frequency range. C: The MFRs of several key neural populations as a function of , with the scale factor . Here four neural populations are considered: SNr (blue dot), excitatory pyramidal neurons (green asterisk), SRN (black circle) and TRN (red square). Two black dashed lines in (C) represent the occurring positions of low and high triggering mean firing rates (TMFRs), respectively. D: The low (red filled circle) and high (green filled square) TMFRs as a function of . For all simulations, the coupling strength of the TRN-SRN pathway is set as .