SOCIAL DISCRIMINATION PROCEDURE - AN ALTERNATIVE METHOD TO INVESTIGATE JUVENILE RECOGNITION ABILITIES IN RATS

Experiments were performed to establish the social discrimination proc edure as an alternative method to the widely used social recognition t est for investigating short-term olfactory memory processes in rats. T he time that 4-mo old male animals spent investigating conspecific juv eniles was taken as an index of their juvenile recognition/discriminat ion abilities. When the same juvenile was reexposed to the adult 30 mi n after its initial exposure, it was investigated at a significantly l ower intensity compared to a simultaneously presented novel juvenile. If the second exposure to the previously exposed juvenile occurred 2 h later, however, both juveniles were investigated equally, indicating an extinction of olfactory memory. The simultaneous presentation of th e previously exposed juvenile and novel juvenile provides not only an internal control under identical experimental conditions (thus reducin g the number of sessions for a given experimental series), hut also th e opportunity to separate specific (i.e., memory-related) from nonspec ific (i.e., investigatory behavior-suppression) effects in pharmacolog ical studies. Furthermore, the social discrimination procedure enables even in sexually naive adult male rats the detection of juvenile reco gnition abilities which seem to be masked in the social recognition te st by sexual/aggressive behavior-motivated investigation. The method d escribed here might be an attractive alternative to the conventional s ocial recognition procedure.