Dopamine agonists and antagonists can produce an attenuation of response bias in a temporal discrimination task depending on discriminability of target duration

Behav Processes. 2006 Feb 28;71(2-3):286-96. doi: 10.1016/j.beproc.2005.11.012. Epub 2006 Jan 4.

Abstract

The current study examined the effects of the D2 agonist (quinpirole) and D2 antagonist (eticlopride) on temporal discrimination performance in a conditional discrimination task (Experiment I) and a delayed conditional discrimination task (Experiment II). In both experiments rats discriminated between a scheduled stimulus duration of 3 s versus 9 s. Consistent with previous reports, overall discrimination performance decreased in a dose-dependent manner with both drugs. Changes in response bias (the tendency to choose-short or choose-long irrespective of actual stimulus duration), however, were best characterized in terms of both drugs tending to attenuate the bias effects normally observed during baseline drug-free performance. Specifically, the 'choose-short' bias observed in Experiment I and at a relatively short, 0.1 s, delay in Experiment II became less extreme with increasing doses. In addition, the 'choose-long' bias observed at a relatively long, 6 s, delay in Experiment II also became less extreme with increasing doses. Thus, whether there was an apparent shift from a short response bias to long, or vice versa, was the product of the delay interval between stimulus presentation and choice rather than whether the drug in question was a D2 agonist or antagonist. Such an attenuation of bias may have arisen because of subjects confounding the delay interval with the actual discriminative stimulus duration.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Choice Behavior / drug effects*
  • Choice Behavior / physiology
  • Conditioning, Psychological / drug effects
  • Conditioning, Psychological / physiology
  • Discrimination Learning / drug effects*
  • Discrimination Learning / physiology
  • Dopamine Agents / pharmacology
  • Male
  • Quinpirole / pharmacology
  • Rats
  • Reaction Time / drug effects*
  • Reaction Time / physiology
  • Receptors, Dopamine D2 / drug effects*
  • Receptors, Dopamine D2 / metabolism
  • Salicylamides / pharmacology
  • Statistics, Nonparametric
  • Time Perception / drug effects*
  • Time Perception / physiology

Substances

  • Dopamine Agents
  • Receptors, Dopamine D2
  • Salicylamides
  • Quinpirole
  • eticlopride