Conditioned increase of locomotor activity induced by haloperidol.

Luis Gonzalo De La Casa,Lucía Cárcel,Auxiliadora Mena,Lucía Vicente,Juan Carlos Ruiz-Salas,Vilfredo De Pascalis

doi:10.1371/journal.pone.0200178

Luis Gonzalo De La Casa, Lucía Cárcel + Show 4 more

Open Access

https://doi.org/10.1371/journal.pone.0200178

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Journal: PloS one	Publication Date: Oct 3, 2018
Citations: 11	License type: CC BY 4.0

Affiliation: Universidad de Sevilla

Abstract

Dopamine antagonist drugs have profound effects on locomotor activity. In particular, the administration of the D2 antagonist haloperidol produces a state that is similar to catalepsy. In order to confirm whether the modulation of the dopaminergic activity produced by haloperidol can act as an unconditioned stimulus, we carried out two experiments in which the administration of haloperidol was repeatedly paired with the presence of distinctive contextual cues that served as a Conditioned Stimulus. Paradoxically, the results revealed a dose-dependent increase in locomotor activity following conditioning with dopamine antagonist (Experiments 1) that was susceptible of extinction when the conditioned stimulus was presented repeatedly by itself after conditioning (Experiment 2). These data are interpreted from an associative perspective, considering them as a result of a classical conditioning process.

Highlights

Pavlovian conditioning has been proposed as a fundamental process to explain how organisms learn to respond adaptively in anticipation of the occurrence of environmental events [1,2]
This procedure has led to seemingly contradictory results, since while in some cases the Conditioned Response (CR) that appears has been similar to that produced by the drug [3,4], on other occasions the CR has been of an opposite nature to that induced by the drugs [5,6]
Eikelboom & Stewart [7] have proposed that the origin of these differences could be related to the effect of the drug on the nervous system: whilst on some occasions the Conditional Stimulus (CS) is associated with an Unconditioned Response (UR) dependent on the central nervous system, at other times the CS is associated with a peripheral UR that will appear to compensate for the central effects of the drug

Summary

Introduction

Pavlovian conditioning has been proposed as a fundamental process to explain how organisms learn to respond adaptively in anticipation of the occurrence of environmental events [1,2].

Results

Conclusion