Figure 1.

Schematic of the animal preparation. The bulla was opened superiorly and posteriorly, and a hole approximately 200 μm in diameter was made in the vestibule for the fiber-optic pressure sensor. The cartilaginous ear canal was cut and a brass tube was glued in the bony ear canal to allow repeatable couplings of the earphone delivering the sound stimuli. A built-in reference microphone measured sound pressure in the ear canal. A laser Doppler vibrometer was aimed at reflective beads placed on the posterior crus and the footplate of the stapes.