Effects of indirect GPe-related pathways on regulating absence seizures.

<p>A, B: Two-dimensional state analysis (A) and frequency analysis (B) in the combined (−<i>v</i>_<i>cp</i>₂, −<i>v</i>_{<i>ζp</i>₂}) and (−<i>v</i>_<i>cp</i>₂, −<i>v</i>_<i>ζe</i>) parameter spaces. Two considered indirect GPe-related pathways are: the inhibitory GPe-STN pathway (A₁, B₁) and the excitatory hyperdirect pathway from pyramidal neurons to STN (A₂, B₂). Three dynamical state regions are observed in the state analysis diagrams: the saturation region (I), the SWD oscillation region (II) and the low firing region (IV). In (A₁) and (A₂), the red dashed lines stand for the default coupling strengths of these two indirect GPe-related pathways, the white dashed lines represent the boundaries of suppression regions of SWDs, and the arrows denote the suppression directions of SWDs. In (B₁) and (B₂), the asterisk (“*”) regions surrounded by black dashed lines are the SWD oscillation regions falling into the 2–4 Hz frequency range. C: The TMFR as a function of −<i>v</i>_<i>cp</i>₂ for the inhibitory GPe-STN pathway (C₁) and the excitatory hyperdirect pathway (C₂). D: The RR as a function of −<i>v</i>_<i>cp</i>₂ for the inhibitory GPe-STN pathway (D₁) and the excitatory hyperdirect pathway (D₂). Compared to the results in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004539#pcbi.1004539.g004" target="_blank">Fig 4</a>, these two indirect GPe-related pathways have relatively weak effects on controlling absence seizures.