delayed self-feedback in the form suggested by Pyragas [@PYR92], where the difference $s(t)-s(t-\tau_K)$ of a system variable $s$ (e.g., activator or inhibitor) at time $t$ and at a delayed time $t-\tau_K$, multiplied by some control amplitude $K$, is coupled back into the same system (Fig. \[fig:scheme\](b)). Such feedback loops might arise naturally in neural systems, e.g., due to neurovascular couplings that has a characteristic latency, or due to finite propagation speed along cyclic connections within a neuron sub-population, or they could be realized by external feedback loops as part of a therapeutical measure, as proposed in Ref. [@POP05]. This feedback scheme is simple to implement, quite robust, and has already been applied successfully in a real experiment with time-delayed neurofeedback from real-time magnetoencephalography (MEG) signals to humans via visual stimulation in order to suppress the alpha rhythm, which is observed due to strongly synchronized neural populations in the visual cortex in the brain [@HAD06]. One distinct advantage of this method is its non-invasiveness, i.e., in the ideal deterministic limit the control force vanishes on the target orbit, which may be a steady state or a periodic oscillation of period $\tau$. In case of noisy dynamics the control force, of course, 