Abstract
The responses of peripheral auditory neurons to two-tone stimuli were used to inferentially examine the nature of cochlear processing during development. Rate suppression was not seen in the youngest animals, and was first observed at 77 gestational days, in units exhibiting adultlike frequency selectivity. Suppression was highly correlated with the degree of tuning, and neurons were segregated into three classes based on these responses. Broadly tuned neurons (type IB) with low characteristic frequencies (CFs) did not exhibit suppression, and were observed early in postnatal life. Sharply tuned, but still immature neurons (type IS) exhibited suppression, but to a lesser degree than mature neurons (type M). One interpretation of these results is that basilar membrane mechanics are linear during the final stages of cochlear development, indicating that the immature signal transduction process is fundamentally different from that of adults.
Original language | English (US) |
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Pages (from-to) | 135-149 |
Number of pages | 15 |
Journal | Hearing Research |
Volume | 77 |
Issue number | 1-2 |
DOIs | |
State | Published - Jun 15 1994 |
Bibliographical note
Funding Information:Data were collected from 70 kittens, ranging in age from 69 to 137 gestational days, and from 13 adult animals, that were older than 240 gestational days (approximately 8 postnatal months) of age. The data collected from these animals were not exclusively directed toward the experiments reported here, thereby inflating the number of subjects required to complete this study. All of the kittens were obtained from an in-house breeding colony, and gestational ages were determined from a 24 hour breeding period. The mean gestational length was 67 + 2 days for the 42 litters which provided animals for this study. Gestational age was used in this investigation to reduce variability that may appear when data are analyzed in terms of postnatal age. The majority of adult cats were obtained from random sources. Animals were housed within the animal facility at Boys Town National Research Hospital (BTNRH). The care and use of all animals were in accordance with the guidelines of the animal welfare committee of Creighton University and BTNRH. This research was supported by NIDCD grants #DC00034 and #DC00982 awarded to EJW.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
Keywords
- Auditory nerve
- Cochlear nuclear complex
- Development
- Two-tone suppression