glottis vocal folds neural oscillator purring frequency
The exact mechanism by which cats purr has long been elusive, but it has been proposed that purring is generated via a series of sudden build-ups and releases of pressure as the glottis is opened and closed, which causes the vocal folds to separate forcefully. The laryngeal muscles in control of the glottis
are thought to be driven by a neural oscillator which generates a cycle of contraction and release every 30–40
milliseconds (giving a frequency of 33 to 25 Hz).
