Extinction of Running-Based Taste Aversion in Rats(Rattus norvegicus)

Abstract

Wheel running establishes conditioned aversion in rats to a taste solution consumed shortly prior to the running. Many studies have shown that this is a case of Pavlovian conditioning, in which the taste and running respectively act as the conditioned stimulus (CS) and the unconditioned stimulus (US), but extinction of this running-based taste aversion has not been explicitly demonstrated. Experiment 1, using a within-subjects design, showed that saccharin aversion formerly established by a single pairing of an exposure to saccharin solution with a running opportunity was extinguished by two daily exposures to the saccharin solution. However, there was no spontaneous recovery from extinction in the tests which were administered 6 and 27 days after the extinction days. Experiment 2, using a between-groups design, successfully demonstrated extinction and spontaneous recovery of running-ba

Effect of pretrial running on running-based taste aversion learning in rats.

“…Rats of Group S ( n = 4 in the first squad and n = 3 in the second squad) were kept in the carrying cart during the pre- and postintake periods; rats of Group SR ( n = 4 in each squad) were kept in the cart during the preintake period but allowed to run in the activity wheels during the postintake period; rats of Group RS ( n = 4 in each squad) were allowed to run during the preintake period but kept in the cart during the postintake period; rats of RSR ( n = 4 in each squad) were allowed to run in the wheels during the pre- and postintake periods. It is notable that the procedure for Group SR (i.e., 15-min saccharin access followed by 15-min wheel running) is a standard treatment in my laboratory to obtain weak running-based CTA in rats (e.g., Hayashi et al, 2002; Nakajima, 2018a; Nakajima et al, 2006): I feared the risk of having the CTA which was too strong to be overcome by the US preexposure treatment.…”

“…The running-based CTA has been replicated in a large number of studies (see Boakes & Nakajima, 2009, for a review) since its discovery by Lett and Grant (1996). Like more conventional, poison-based CTA, the running-based CTA has shown many behavioral features of Pavlovian conditioning, including laws of contiguity and US strength (Hayashi, Nakajima, Urushihara, & Imada, 2002), extinction and spontaneous recovery (Nakajima, 2018a), CS-preexposure effect (or latent inhibition; Heth & Pierce, 2007; Satvat & Eikelboom, 2006; Sparkes, Grant, & Lett, 2003), degraded contingency effect (Nakajima, 2008), inhibitory learning by backward conditioning (Dobek, Heth, & Pierce, 2012; Hughes & Boakes, 2008; Salvy, Pierce, Heth, & Russell, 2004), stimulus overshadowing (Nagaishi & Nakajima, 2010), associative blocking (Pierce & Heth, 2010), and higher order contextual control (Hashimoto & Nakajima, 2013).…”