TY - JOUR
T1 - Direct visualization of organ of corti kinematics in a hemicochlea
AU - Hu, Xintian
AU - Evans, Burt N.
AU - Dallos, Peter
PY - 1999
Y1 - 1999
N2 - The basilar membrane in the mammalian cochlea vibrates when the cochlea receives a sound stimulus. This mechanical vibration is transduced into hair cell receptor potentials and thereafter encoded by action potentials in the auditory nerve. Knowledge of the mechanical transformation that converts basilar membrane vibration into hair cell stimulation has been limited, until recently, to hypothetical geometric models. Experimental observations are largely lacking to prove or disprove the validity of these models. We have developed a hemicochlea preparation to visualize the kinematics of the cochlear micromechanism. Direct mechanical drive of 1-2 Hz sinusoidal command was applied to the basilar membrane. Vibration patterns of the basilar membrane, inner and outer hair cells, supporting cells, and tectorial membrane have been recorded concurrently by means of a video optical flow technique. Basilar membrane vibration was driven in a direction transversal to its plane. However, the direction of the resulting vibration was found to be essentially radial at the level of the reticular lamina and cuticular plates of inner and outer hair cells. The tectorial membrane vibration was mainly transversal. The transmission ratio between cilia displacement of inner and outer hair cells and basilar membrane vibration is in the range of 0.7-1.1. These observations support, in part, the classical geometric models at low frequencies. However, there appears to be less tectorial membrane motion than predicted, and it is largely in the transversal direction.
AB - The basilar membrane in the mammalian cochlea vibrates when the cochlea receives a sound stimulus. This mechanical vibration is transduced into hair cell receptor potentials and thereafter encoded by action potentials in the auditory nerve. Knowledge of the mechanical transformation that converts basilar membrane vibration into hair cell stimulation has been limited, until recently, to hypothetical geometric models. Experimental observations are largely lacking to prove or disprove the validity of these models. We have developed a hemicochlea preparation to visualize the kinematics of the cochlear micromechanism. Direct mechanical drive of 1-2 Hz sinusoidal command was applied to the basilar membrane. Vibration patterns of the basilar membrane, inner and outer hair cells, supporting cells, and tectorial membrane have been recorded concurrently by means of a video optical flow technique. Basilar membrane vibration was driven in a direction transversal to its plane. However, the direction of the resulting vibration was found to be essentially radial at the level of the reticular lamina and cuticular plates of inner and outer hair cells. The tectorial membrane vibration was mainly transversal. The transmission ratio between cilia displacement of inner and outer hair cells and basilar membrane vibration is in the range of 0.7-1.1. These observations support, in part, the classical geometric models at low frequencies. However, there appears to be less tectorial membrane motion than predicted, and it is largely in the transversal direction.
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U2 - 10.1152/jn.1999.82.5.2798
DO - 10.1152/jn.1999.82.5.2798
M3 - Article
C2 - 10561446
AN - SCOPUS:0032719753
VL - 82
SP - 2798
EP - 2807
JO - Journal of Neurophysiology
JF - Journal of Neurophysiology
SN - 0022-3077
IS - 5
ER -