Editing Phonation (section)

===Neurochronaxic theory===
This theory states that the frequency of the vocal fold vibration is determined by the [[chronaxie]] of the recurrent nerve, and not by breath pressure or muscular tension.  Advocates of this theory thought that every single vibration of the vocal folds was due to an impulse from the recurrent laryngeal nerves and that the acoustic center in the brain regulated the speed of vocal fold vibration.<ref name="McKinney"/>  Speech and voice scientists have long since abandoned this theory as the muscles have been shown to not be able to contract fast enough to accomplish the vibration.  In addition, persons with paralyzed vocal folds can produce phonation, which would not be possible according to this theory.  Phonation occurring in excised larynges would also not be possible according to this theory.