Figure 1: Representative experimental preparation of the P5-10 chicken basilar papilla.

(a) Microdissected inner ear tissues in which the surrounding otic capsule bone has been removed. The semicircular canals are the tubular structures to the right. The lagena is at the apical end of the basilar papilla. The three locations along the length of the basilar papilla that we imaged in vivo (50, 75 and 85% from the base) are highlighted. (b) View after opening the middle ear bulla widely in a post-mortem chicken. This involved removing about half of the tympanic membrane. The columella that connects the tympanic membrane to the base of the basilar papilla is seen. An artery angles over basilar papilla. (c) In vivo view. (d) Frozen section across the basilar papilla 75% from the base. Tuning curves were measured at the SHC/BM region (orange dot) and the THC/TM region (red dot). (e) Illustration of the chicken basilar papilla. Scala vestibuli (SV), scala media (SM), scala tympani (ST), tegmentum vasculosum (TV), fibrocartilage plate (FcP), auditory nerve ganglion cells (G). (f–h) In vivo VOCTV images across the basilar papilla 50, 75 and 85% from the base. (i,j) ABR waveforms in one representative live chicken immediately after induction of anaesthesia, before surgery and repeated again after surgery to open the middle ear bulla and performing vibrometry experiments. There was no change in waveform morphology. The stimuli were clicks of intensity from 30 to 80 dB SPL in 5 dB steps. (k) Peak-to-peak responses from the ABR signals as a function of stimulus intensity. (l) CM magnitude responses to 2.75 kHz tones that ranged in intensity from 30 to 80 dB SPL in 5 dB steps. Error bars show the s.e.m.