Vol.:(0123456789) 1 3 Animal Cognition https://doi.org/10.1007/s10071-020-01415-x ORIGINAL PAPER Taste association capabilities difer in high‑ and low‑yawning rats versus outbred Sprague–Dawley rats after prolonged sugar consumption María‑Isabel Miranda 1  · Alejandro Rangel‑Hernández 1  · Gabriela Vera‑Rivera 1  · Carmen Cortes 2  · Jose R. Eguibar 2,3 Received: 28 October 2019 / Revised: 3 June 2020 / Accepted: 10 July 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Yawning is a stereotypical behavior pattern commonly associated with other behaviors such as grooming, sleepiness, and arousal. Several diferences in behavioral and neurochemical characteristics have been described in high-yawning (HY) and low-yawning (LY) sublines from Sprague–Dawley (SD) rats that support they had changes in the neural mechanism between sublines. Diferences in behavior and neurochemistry observed in yawning sublines could also overlap in processes needed during taste learning, particularly during conditioned taste aversion (CTA) and its latent inhibition. Therefore, the aim of this study was to analyze taste memory diferences, after familiarization to novel or highly sweet stimuli, between yawning sublines and compare them with outbred SD rats. First, we evaluated changes in appetitive response during long-term sugar consumption for 14 days. Then, we evaluated the latent inhibition of CTA strength induced by this long pre-exposure, and we also measured aversive memory extinction rate. The results showed that SD rats and the two sublines developed similar CTA for novel sugar and signifcantly stronger appetitive memory after long-term sugar exposure. However, after 14 days of sugar exposure, HY and LY sublines were unable to develop latent inhibition of CTA after two acquisition trials and had a slower aversive memory extinction rate than outbreed rats. Thus, the inability of the HY and LY sublines to develop latent inhibi- tion of CTA after long-term sugar exposure could be related to the time/context processes involved in long-term appetitive re-learning, and in the strong inbreeding that characterizes the behavioral traits of these sublines, suggesting that inbreeding afects associative learning, particularly after long-term exposure to sweet stimuli which refects high familiarization. Keywords Novelty · Appetitive memory · Sugar preference · Latent inhibition · Extinction · Sucrose · Aversive conditioning Introduction Yawning is an innate behavioral pattern with very low frequency in all species, including rats (Baenninger 1987), and it is commonly associated with other behaviors such as grooming, penile erection, sleepiness, and arousal (Hol- mgren et al. 1985; Eguibar and Moyaho 1997; Portillo et al. 2010; Krestel et al. 2018). In outbred Sprague–Daw- ley (SD) rats, spontaneous yawning behavior is around 1 yawn/h, but we selectively bred 2 sublines, over 88 genera- tions, that difer in their spontaneous yawning frequency, the high-yawning (HY) subline with 20 yawns/h, and the low-yawning (LY) subline with less than 1 yawn/h (Urba- Holmgren et al. 1990; Eguibar et al. 2002). Using the HY subline, we clearly demonstrated that yawning behavior has a circadian oscillation with a clear peak before dusk (Anias et al. 1984), and restricted feeding schedule is a stronger zeitgeber (Holmgren et al. 1991). Furthermore, several diferences in behavioral characteristics have been described between sublines. For example, HY male rats had more grooming bouts after exposure to a novel envi- ronment or after wetting their fur with respect to LY rats * María-Isabel Miranda mirandami@unam.mx 1 Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla No. 3001, A.P. 1-1141, Juriquilla, Querétaro 76230, Mexico 2 Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico 3 Dirección General de Investigación, Vicerrectoría de Investigación y Estudios de Posgrado, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico