title: Variable delay-to-signal: a fast paradigm for assessment of aspects of impulsivity in rats.
abstract: Testing impulsive behavior in rodents is challenging and labor-intensive. We developed a new behavioral paradigm-the Variable Delay-to-Signal (VDS) test-that provides rapid and simultaneous assessment of response and decision impulsivity in rodents. Presentation of a light at variable delays signals the permission for action (nose poke) contingent with a reward. 2 blocks of 25 trials at 3 s delay flank a block of 70 trials in which light is presented with randomly selected 6 or 12 s delays. Exposure to such large delays boosts the rate of premature responses when the delay drops to 3 s in the final block, an effect that is blunted by an acute methamphetamine challenge and that correlates with the delay-discounting (DD) paradigm (choice impulsivity). Finally, as expected, treatment with the NMDA antagonist MK-801 caused a generalized response increase in all VDS blocks. The pharmacological validation, particularly with methamphetamine which has a well established dual effect on response and decision impulsivity, and the correlations between the impulsive behavior in the DD and VDS paradigms, suggests that the later is able to provide, in a single session, a multi-dimensional assessment of impulsive behavior.
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho Braga, Portugal ; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal.
authors.forename: Hugo
authors.initials: H
authors.lastname: Leite-Almeida
authors.forename: António
authors.initials: A
authors.lastname: Melo
authors.forename: José M
authors.initials: JM
authors.lastname: Pêgo
authors.forename: Sara
authors.initials: S
authors.lastname: Bernardo
authors.forename: Nuno
authors.initials: N
authors.lastname: Milhazes
authors.forename: Fernanda
authors.initials: F
authors.lastname: Borges
authors.forename: Nuno
authors.initials: N
authors.lastname: Sousa
authors.forename: Armando
authors.initials: A
authors.lastname: Almeida
authors.forename: João J
authors.initials: JJ
authors.lastname: Cerqueira
keywords: 5-csrtt; MK-801; decision impulsivity; delay-discounting; methamphetamine; response impulsivity; rodent behavior