Document Detail

Psychometric functions for level discrimination and the effects of signal duration in the goldfish (Carassius auratus): psychophysics and neurophysiology.
MedLine Citation:
PMID:  1512323     Owner:  NLM     Status:  MEDLINE    
Classical conditioning of respiration was used to obtain psychometric functions for pulsed tone level discrimination in the goldfish (Carassius auratus). Conditioned respiratory suppression is a graded response that has some properties of a confidence rating measure. These properties were used to obtain receiver operating characteristics (ROC) and psychometric functions using a blocked method of constant stimuli. Empirical ROCs and neurometric functions were also obtained for single auditory-nerve fibers using spike count as the decision variable in order to evaluate a simple rate code for level discrimination. Psychometric and neurometric functions for level discrimination are similar in showing the same general form (summarized by Weibull functions) that is independent of signal duration. The lower slope of neurometric functions compared with behavioral functions for level discrimination is in accord with similar data on sound detection and vision in nonhuman mammals. Both neural and psychophysical level discrimination thresholds decline with increasing duration (20 to 320 ms), with similar slopes except at short signal durations (20 to 50 ms). At these durations, the animal's use of a channel-selection strategy and neural information following stimulus offset could reduce the difference between neural and psychophysical thresholds. The slopes of the neural and psychophysical duration functions are similar to those for human observers, but the majority of auditory-nerve fibers sampled have lower level discrimination thresholds than the behaving animal. Since human observers perform better than the majority of neurons in level discrimination, well-trained human listeners may be able to select channels with superior information, or to combine information across channels in ways that the goldfish and other animals do not. In general, one is encouraged to believe that neural mechanisms need not be more complex or sensitive than those considered here to account for pure-tone level discrimination in fishes, humans, and other vertebrates.
R R Fay; S L Coombs
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of the Acoustical Society of America     Volume:  92     ISSN:  0001-4966     ISO Abbreviation:  J. Acoust. Soc. Am.     Publication Date:  1992 Jul 
Date Detail:
Created Date:  1992-09-30     Completed Date:  1992-09-30     Revised Date:  2006-12-27    
Medline Journal Info:
Nlm Unique ID:  7503051     Medline TA:  J Acoust Soc Am     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  189-201     Citation Subset:  IM    
Department of Psychology, Loyola University, Chicago, Illinois 60626.
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MeSH Terms
Auditory Threshold / physiology*
Goldfish / physiology*
Loudness Perception / physiology*
Nerve Fibers / physiology
Time Factors
Vestibulocochlear Nerve / physiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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