Measuring Behavior 2005: Schroeder and Desor

The behavioral differentiation between the Carrier and the Non-Carrier profile in groups subjected to the diving-for-food situation: A complex social model to study anxiety in rodents

H. Schroeder and D. Desor

Neurosciences Comportementales, URAPA, INPL-UHP, Vandoeuvre, France

The diving-for-food situation is a complex social task that consists of rats swimming in apnea to reach food through a fully immersed pool, bringing a pellet back to the cage and eating it. The progressive immersion of the only way of access to the feeder induces the emergence of a social differentiation in a group of 6 rats between the Carriers who dive and swim to get food, and the Non-Carriers who never dive and get their food only by stealing it from Carriers. The social differentiation regularly happens with respective proportions of Carriers and Non-Carriers that are very closed to 50%. It remains stable for several months and has been observed in both mice and rats. Two environmental constraints are of importance in the emergence of individual roles: a physical one associated with swimming in apnea across the aquarium to get food, and a social one corresponding to the competition with conspecific cagemates for the possession of food. Ethological studies and pharmacological investigations suggest a role for individual characteristics related to anxiety towards the water constraint and the social context of this task in the acquisition of the Carrier or Non Carrier profile. Recently, the statistical analysis of behavioral data measured from birth to the adulthood in 60 rats, including the weight evolution, the neuro-motor maturation, the exploration of novelty, the reaction to anxiogenic situations and the dominance rank during competition for food, indicates that the social profiles of rats in the diving-for-food task are highly predictable from developmental characteristics of individuals, mainly related to anxiety. All these results provide evidences that the diving-for-food situation seems to be relevant in order to investigate the neurobiological substrates of anxiety related to the social adaptation of a group faced to an environmental constraint, and may be a suitable model to study the pharmacological properties of various drugs like anxiolytics or psychoactive substances.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.