Zero phase-lag synchronization through short-term modulations

Considering coupled phase model oscillator systems with non-identical time delays, we study the possibility of close-to-zero phaselag synchronization (ZPS) without frequency depression (FD). FD refers to nearly vanishing frequencies of the synchronized oscillators (in comparison to the intrinsic frequencies); its absence is crucial for interpretations related to brain dynamics. Discussing an extension of the Kuramoto model, it is demonstrated that ZPS without FD may arise by allowing for dynamical parameters. Two models are presented: one is based on shortterm modulation of the delays, while the other assumes static delays but short-term modulation of coupling strengths. We also speculate on possible relevance of such mechanisms with respect to assembly formation by relating the frequency of the synchronized oscillation to recently proposed pattern frequency bands.