| Abstract #341, Date 2/15/99, Session K4, Poster (B88) |
| Vibration of reflective beads placed on the basilar membrane |
| *N.P. Cooper (University of Bristol) |
To date, very few observations of the cochlea's mechanics have been made without the need to place small objects (either reflective micro-beads, mirrors or radioactive sources) on the cochlear partition. Much of our knowledge of the partition's motion is hence based on untested assumptions concerning the effects of these objects. One recent study of an isolated temporal bone preparation (Khanna et al., 1998; Hearing Research 116, 71-85) has highlighted this problem, by claiming that beads placed on the basilar membrane in the apical turns of the cochlea do not follow the underlying motion of the cochlear partition. The present study was designed to investigate this issue in the more basal turns of living cochleae, where most previous studies of basilar membrane motion have been performed. Mechanical responses to pure tones were recorded from the basilar membrane in the basal turn and hook regions of the guinea-pig cochlea using a displacement-sensitive laser interferometer. The animals were deeply anaesthetised throughout the experimental procedures, and were lethally overdosed on completion of the in vivo measurements. Gold-coated polystyrene microbeads, of the type used in many previous investigations, were used as reflective objects. No significant differences were observed between the motions of these beads and those of the adjacent regions of the basilar membrane. |