Effects of morphine on temporal discrimination and color matching: general disruption of stimulus control or selective effects on timing?

Full Abstract

Discrepant effects of drugs on behavior maintained by temporal-discrimination procedures make conclusive statements about the neuropharmacological bases of timing difficult. The current experiment examined the possible contribution of a general, drug-induced disruption of stimulus control. Four pigeons responded on a three-component multiple schedule that included a fixed-interval 2-min, temporal discrimination, and color-matching component. Under control conditions, response rates and choice responses during the first two components showed evidence of control by time, and accuracy for color matching was high in the third component. Morphine administration flattened the distribution of fixed-interval responding and produced a general disruption of accuracy in the temporal-discrimination component, whereas accuracy in the color-matching component was relatively unaffected. Analysis of the psychophysical functions from the temporal-discrimination component indicated that morphine decreased accuracy of temporal discrimination by decreasing overall stimulus control, rather than by selectively affecting timing. These results suggest the importance of determining the neurophysiological bases of stimulus control as it relates to temporal discrimination.

Author information

Author/s: Ward, Ryan D (RD); Odum, Amy L (AL);

Affiliation: Department of Psychology, Utah State University, Logan 84322-2810, USA. RyanWard(-atsign-)cc.usu.edu

Journal and publication information

Publication Type: Journal Article

Journal: Journal of the experimental analysis of behavior (J Exp Anal Behav), published in United States. (Language: eng)

Reference: 2005-Nov; vol 84 (issue 3) : pp 401-15

Dates: Created 2006/04/06; Completed 2006/09/08; Revised 2008/11/20;

PMID: 16596972, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

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