Olfactory repeated discrimination reversal in rats: Effects of chlordiazepoxide, dizocilpine, and morphine

Mark Galizio, Laurence L Miller, Adam Ferguson, Patrick McKinney, Raymond C. Pitts

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Effects of a benzodiazepine (chlordiazepoxide), an N-methyl-D-aspartate receptor antagonist (dizocilpine), and an opiate agonist (morphine) were studied with a procedure designed to assess effects of drugs and other manipulations on nonspatial learning in rats. In each session, rats were exposed to 2 different 2-choice odor-discrimination problems with food reinforcement for correct responses. One problem (performance discrimination) remained the same throughout the study. That is, 1 odor was always correct (S+) and the other was never correct (S-). For the other problem (reversal discrimination), stimuli changed every session. Six different odors were used to program the reversal discrimination; on any given session, S+ was a stimulus that had served as S- the last time it had appeared, S- was a stimulus that had been S+ on its last appearance. Thus, in each session, learning a discrimination reversal could be studied along with the performance of a comparable, but previously learned, discrimination. Chlordiazepoxide interfered with reversal learning at doses that had no effect on the performance discrimination. Morphine and dizocilpine also impaired reversal learning but only at doses that also affected performance of the well-learned performance discrimination.

Original languageEnglish (US)
Pages (from-to)1175-1179
Number of pages5
JournalBehavioral Neuroscience
Issue number5
StatePublished - Oct 2006
Externally publishedYes


  • Benzodiazepine
  • Learning
  • Morphine
  • NMDA antagonist
  • Odor discrimination
  • Repeated acquisition

ASJC Scopus subject areas

  • Behavioral Neuroscience


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