Is it possible to replace stimulus animals by scent-filled cups in the social discrimination test?

Abstract

A study in which the rat social discrimination test was refined is described. This test measures social memory by using, in general, juvenile rats as stimulus animals. Rats are offered a first juvenile to investigate (learning trial), and after a specified interval, the rats are offered the same rat and a second juvenile rat to investigate again (retrieval trial). When the rats sniff the second juvenile in the retrieval trial more than the first, social memory for the second juvenile is said to be present. This test is mainly based on scents from the juvenile. Attempts were made to refine the test to reduce the number of animals used, to enhance the scope of the test, and to improve its validity. Firstly, the stimulus animals were replaced by the scent of juveniles, in the form of cups filled with sawdust taken from cages of juvenile rats. Similar results to those in the original test were obtained when using these scents. Furthermore, male and female scents were tested, and showed the same results as for the juvenile scents. Secondly, rats were also given two cups (one scent-filled and one filled with plain sawdust) in the learning trial, to determine which allowed a more-precise delineation of motivational, discriminatory and memory components. Overall, it is possible to replace stimulus animals by scent-filled cups in the social discrimination test, to enhance the scope of the test, and to draw more-valid conclusions with respect to social memory.