Hearing thresholds of normal and fenestrated deaf pigeons. A behavioural study on hearing with the vestibular organ.

Hearing thresholds were measured for 5 normal pigeons with the heart-rate conditioning method. After extirpation of the membranous cochlea on both sides and fenestration of the lateral canals, hearing thresholds were measured again with the same method at 250, 750 and 1500 Hz. Hearing thresholds found in this way for deaf fenestrated pigeons correspond very well to threshold values for the "Tullio effect". Electrical activity in the vestibular nerve evoked by sound is thought to be the origin of these phenomena.