Differential acquisition, extinction, and reinstatement of conditioned suppression in mice

Abstract

In animals, the reappearance of conditioned fear responses after extinction has been primarily investigated using single-cue conditioning paradigms. However, a differential paradigm can overcome several of the disadvantages associated with a single-cue procedure. In the present study, the reinstatement phenomenon was assessed in mice using a differential conditioned suppression paradigm. In a first phase, one conditioned stimulus (CS + ) was consistently paired with an unconditioned stimulus (US; footshock) while another CS (CS–) was not, resulting in selective suppression of previously trained instrumental behaviour during the CS + . After the extinction phase, half of the animals (reinstatement group) were presented with unsignalled USs, while the other half were not (control group). A differential return of conditioned responding was observed in the reinstatement group, but not in the control group. The implications of these findings for future conditioning research are discussed.

Acknowledgments

This research was supported by a University of Leuven grant GOA/2001/01 to the Centre for the Psychology of Learning and Experimental Psychopathology and the KUL2004 Impulse Programme to the Laboratory of Biological Psychology.

Notes

¹ When the animals were tested in groups of 4 (from Extinction Session 17 up until Test Session 5), the CSs and USs were also presented in the four empty operant chambers to keep the (total) intensity of the auditive stimuli in the room similar to that in the other sessions. Due to a procedural error in Test Session 1, half of the animals of every condition were run without the stimuli also being presented in the empty operant chambers in that test session.

²For 8 animals the data of the 15th extinction session were lost due to a technical error.

Additional information

Notes on contributors

Tom Beckers

Tom Beckers is postdoctoral fellows of the Research Foundation–Flanders (FWO–Vlaanderen).

Debora Vansteenwegen

Debora Vansteenwegen is postdoctoral fellows of the Research Foundation–Flanders (FWO–Vlaanderen).