Genetically-based behavioral traits influence the effects of Shuttle Box avoidance overtraining and extinction upon intertrial responding: a study with the Roman rat strains.
In the present study, we evaluated the effects of extended exposure procedures to contextual fear cues as a way of reducing intertrial responses (ITRs), a characteristic stereotyped behavior displayed in 2-way Shuttle Box avoidance overtraining. We used rat strains psychogenetically selected for efficient (Roman high-avoidance; RHA) versus poor 2-way Shuttle Box performance (Roman low-avoidance; RLA), the former being fearless/impulsive relative to the latter. Additionally, Sprague-Dawley (SD) rats were compared with RHAs to have a measure of the ITRs exhibited by another, non-selected group of animals. The main findings were that after extended exposure RHAs diminished their ITRs without affecting avoidance performance, although they emitted a pattern of ITRs somewhat excessive as compared with SDs. We concluded that three factors could influence the expression of ITRs in RHA rats: (1) the repetitive and stereotyped responding induced by 2-way Shuttle Box overtraining; (2) contextual fear conditioning; and (3) a genetic background associated with high impulsiveness.
Aguilar
Raúl
R
Medical Psychology Unit, Department of Psychiatry and Forensic Medicine, School of Medicine, Institute of Neurosciences, Autonomous University of Barcelona, Bellaterra, Barcelona 08193, Spain. raul.aguilar@telefonica.net
Gil
Luis
L
Fernández-Teruel
Alberto
A
Tobeña
Adolf
A
D000818:Animals; D001362:Avoidance Learning; D001522:Behavior, Animal / Q000502:physiology*; D003213:Conditioning, Psychological; D005108:Extinction, Psychological; D005239:Fear; D051381:Rats; D017207:Rats, Sprague-Dawley