From phase advance to phase delay: Flexible coordination between neuronal rhythms by the duration of synaptic input

Abstract

Coupled neuronal oscillators generate a wide range of dynamic activity patterns that drive various behaviors in animals. A single neural circuit can generate multiple activity patterns and switch between them by tuning the coordination between its component oscillators. However, the mechanisms underlying how neural circuits dynamically tune the phase relationship between oscillators are not fully understood. We studied the phase relationships between two unidirectionally coupled oscillators and found that the duration of synaptic input to the driven oscillator controls the phase difference between them. The phase difference can smoothly change over a wide range, from large phase advances to phase delays, with variations in the duration of synaptic input. The control of the phase difference derives from the entrainment properties shared by commonly used neural oscillators, particularly when they are close to their relaxation limit. We applied our findings on the control of phase difference to a chain of unidirectionally synaptically coupled identical oscillators. We demonstrated that the direction and speed of activity propagation in the chain can be controlled by the duration of synaptic input.