Document Detail


Threshold shifts and enhancement of cortical evoked responses after noise exposure in rats.
MedLine Citation:
PMID:  10601713     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effect of exposure to various types of noise (broadband, high-frequency or low-frequency) was studied in adult pigmented rats. Thresholds and amplitudes of middle latency responses (MLR) recorded from electrodes implanted on the surface of the auditory cortex were analyzed before and after noise exposure. Exposure to noise with intensities ranging from 105 to 120 dB for 1 h produced only temporary threshold shifts (TTS). Exposure to broadband noise produced TTS throughout the whole frequency range of the rat's hearing, mostly expressed at frequencies of maximal hearing sensitivity (16-32 kHz). Hearing loss produced by high- or low-frequency noise exposure was related to the spectral characteristics of the noise. The exposure to high-intensity noise may also result in amplitude enhancement of the MLR. This phenomenon was seen mainly after broadband noise exposure and occurred in response to both low-frequency and high-frequency test stimuli. High-frequency and low-frequency noise produced amplitude enhancement mainly at frequencies which corresponded to the maximum exposure energy. In contrast to the relatively similar values of TTS obtained in different rats under the same conditions of noise exposure, great inter-individual variability was found in the MLR amplitude enhancement. In all rats the dynamics of recovery functions for amplitude enhancement were different from those for MLR thresholds. The data indicate that whereas post-exposure TTS are related to peripheral changes, the post-exposure MLR amplitude enhancement is most probably connected with a change in the processing of auditory information in the central nervous system.
Authors:
J Syka; N Rybalko
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Hearing research     Volume:  139     ISSN:  0378-5955     ISO Abbreviation:  Hear. Res.     Publication Date:  2000 Jan 
Date Detail:
Created Date:  2000-02-04     Completed Date:  2000-02-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7900445     Medline TA:  Hear Res     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  59-68     Citation Subset:  IM    
Affiliation:
Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20, Prague, Czech Republic. syka@biomed.cas.cz
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MeSH Terms
Descriptor/Qualifier:
Acoustic Stimulation
Animals
Auditory Cortex / physiopathology*
Auditory Threshold / physiology*
Evoked Potentials, Auditory / physiology*
Female
Hearing Loss, Noise-Induced / physiopathology*
Noise / adverse effects*
Rats

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