Figure 4.

Suppression of synchronization in the STN-GPe neuronal populations (1)–(4) by adaptive HF DBS. (A–C) Time courses of the filtered LFP (green curves) and the order parameter $\langle R\rangle$ (blue curves, scaled by the factor 1/25) of STN neurons stimulated by aDBS started at $t=20\mathrm{s}$ for the interphase gap (A) $GW=0\mathrm{ms}$ and (B,C) $GW=2\mathrm{ms}$ and stimulation intensity (A,B) $K=1.2$ and (C) $K=2$. The scaled value of $\langle R\rangle$ of the synchronized and stimulation-free STN neurons [Fig. 1A, black curve, and Fig. 3A for $K=0$] is indicated by horizontal blue dashed lines for comparison. The red stepwise curves indicate the on- and off-epochs of aDBS for the LFP thresholds $T{h}_{\mathrm{on}}=0.016$ (upper value of the red stepwise curves) and $T{h}_{\mathrm{off}}=0.008$ (black horizontal line). (D–F) Averaged order parameter $\langle R\rangle$ versus stimulation intensity K for aDBS (filled symbols) and cDBS (dashed curves, copied from Fig. 3A for comparison) as indicated in the legends for the interphase gap (D) $GW=0\mathrm{ms}$, (E) 2 ms, and (F) 5 ms. The standard deviation of the order parameter fluctuations for aDBS is indicated by error bars. The fraction of the stimulation time T_on (black diamonds) of aDBS, where HF DBS was switched on, and its smoothed values (black dotted curves) are also shown.