title: Differential memory persistence of odor mixture and components in newborn rabbits: competition between the whole and its parts.
abstract: Interacting with the mother during the daily nursing, newborn rabbits experience her body odor cues. In particular, the mammary pheromone (MP) contained in rabbit milk triggers the typical behavior which helps to localize and seize the nipples. It also promotes the very rapid appetitive learning of simple or complex stimuli (odorants or mixtures) through associative conditioning. We previously showed that 24 h after MP-induced conditioning to odorants A (ethyl isobutyrate) or B (ethyl maltol), newborn rabbits perceive the AB mixture in a weak configural way, i.e., they perceive the odor of the AB configuration in addition to the odors of the elements. Moreover, after conditioning to the mixture, elimination of the memories of A and B does not affect the memory of AB, suggesting independent elemental and configural memories of the mixture. Here, we evaluated whether configural memory persistence differs from elemental one. First, whereas 1 or 3-day-old pups conditioned to A or B maintained their responsiveness to the conditioned odorant for 4 days, those conditioned to AB did not respond to the mixture after the same retention period. Second, the pups conditioned to AB still responded to A and B 4 days after conditioning, which indicates stronger retention of the elements than of the configuration when all information are learned together. Third, we determined whether the memory of the elements competes with the memory of the configuration: after conditioning to AB, when the memories of A and B were erased using pharmacological treatment, the memory of the mixture was extended to day 5. Thus, newborn rabbits have access to both elemental and configural information in certain odor mixtures, and competition between these distinct representations of the mixture influences the persistence of their memories. Such effects certainly occur in the natural context of mother-pup interactions and may contribute to early acquisition of knowledge about the surroundings.
authors: Centre des Sciences du Goût et de l'Alimentation (CSGA), UMR 6265 CNRS, UMR 1324 INRA, Université de Bourgogne Dijon, France.
authors: Gérard
authors: G
authors: Coureaud
authors: Centre des Sciences du Goût et de l'Alimentation (CSGA), UMR 6265 CNRS, UMR 1324 INRA, Université de Bourgogne Dijon, France.
authors: Thierry
authors: T
authors: Thomas-Danguin
authors: Centre des Sciences du Goût et de l'Alimentation (CSGA), UMR 6265 CNRS, UMR 1324 INRA, Université de Bourgogne Dijon, France.
authors: Frédérique
authors: F
authors: Datiche
authors: Department of Child and Adolescent Psychiatry, New York University Langone School of Medicine New York, NY, USA.
authors: Donald A
authors: DA
authors: Wilson
authors: Nutrition and Integrative Neurobiology Group, INRA UMR 1286 Bordeaux, France ; Université de Bordeaux Bordeaux, France.
authors: Guillaume
authors: G
authors: Ferreira
keywords: Oryctolagus cuniculus; configural perception; memory persistence; newborn; odor mixture; retention; stimulus representation