Figure 4From: Phase-dependence of response curves to deep brain stimulation and their relationship: from essential tremor patient data to a Wilson–Cowan modelIllustration of the approach taken to derive expressions for the phase and amplitude responses in the linearisation of a 2D focus model. Top: phase plane, bottom: time series of \(X_{1}\). The tremor is modelled by \(X_{1}\), and the stimulation \(\delta X_{1}\) is applied to \(X_{1}\). The system shown corresponds to the linearised fit of patient 1 as described in Sect. 6.1Back to article page