This letter studies frequency-locked rotations in a phase-locked loop (PLL) circuit as FM demodulator. A rotation represents a desynchronized steady state in the PLL circuit and is regarded as another type of self-excited oscillations with natural rotation frequencies. The rotation frequency can be locked at driving frequencies of modulation signals. This letter shows response curves for harmonic amplitude of frequency-locked rotations. They have several different features from response curves of van der Pol oscillator.

The cardio-music synchrogram, which is a visualization tool that helps us observe the phase synchronization between heartbeats and beats of music, is originated in cardio-respiratory synchrogram. In this paper, we proposed a novel statistical method for detecting synchronization periods in cardio-music synchrogram (CMS), and reported the synchronization periods of the cardiac activity for 8 subjects in a listening experiments. Our approach focused on the difference between the statistical distributions of the correlation coefficient calculated for the CMS in a control experiment and in the CMS in the listening experiment.

The mechanism of environment-dependent self-organization of "positional information" in a coupled nonlinear oscillator system is proposed as a new principle of realtime coordinative control in biological distributed system. By modeling the pattern formation in tactic response of Physarum plasmodium, it is shown that a global phase gradient pattern self-organized by mutual entrainment encodes not only the positional relationship between subsystems and the total system but also the relative relationship between internal state of the system and the environment.