Pharmacological studies of performance on the free-operant psychophysical procedure

S Body, T H C Cheung, L Valencia-Torres, C M Olarte Sanchez, K C F Fone, C M Bradshaw, E Szabadi

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10 Citations (Scopus)


In the free-operant psychophysical procedure (FOPP), reinforcement is provided intermittently for responding on lever A in the first half and lever B in the second half of a trial. Temporal differentiation is measured from the psychometric function (percent responding on B, %B, versus time from trial onset, t), the index of timing being T50, the value of t at %B=50. T50 is reduced by acute treatment with 5-hydroxytryptamine (5-HT1A, 5-HT2A) and dopamine (D1-like, D2-like) receptor agonists. The effects of the agonists can be reversed by the respective antagonists of these receptors. Evidence is reviewed suggesting that the effect of endogenous 5-HT is mediated by 5-HT2A receptors and the effect of endogenous dopamine by D1-like receptors. Data are presented on the effects of lesions of the prefrontal cortex and corpus striatum on the sensitivity of performance on the FOPP to D1-like and D2-like receptor agonists. Lesions of the nucleus accumbens, but not the dorsal striatum or prefrontal cortex, attenuated the effects of a D1-like receptor agonist, 6-chloro-2,3,4,5-tetrahydro-1-phenyl-1H-3-benzazepine [SKF-81297], but not a D2-like receptor agonist, quinpirole, on T50. The results indicate that a population of D1-like receptors in the ventral striatum may contribute to the control of timing performance on the FOPP.
Original languageEnglish
Pages (from-to)71-89
Number of pages19
JournalBehavioural Processes
Publication statusPublished - May 2013

Bibliographical note

Copyright © 2013 Elsevier B.V. All rights reserved.


  • interval timing
  • free-operant psychophysical procedure
  • 5-HT receptors
  • dopamine receptors
  • prefrontal cortex
  • corpus striatum


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