Mihalick, S. M., Langlois, J. C., Krienke, J. D., & Dube, W. V. (2000).
An olfactory discrimination procedure for mice.
Journal of the Experimental Analysis of Behavior,
73, 305-318.
This paper describes an olfactory discrimination procedure for
mice that is inexpensively implemented and leads to rapid
discrimination learning. Mice were first trained to dig in small
containers of sand to retrieve bits of buried chocolate. For
discrimination training, two containers were presented
simultaneously for eight trials per session. One container held
sand mixed with cinnamon, and the other held sand mixed with
nutmeg. Both containers were baited with chocolate buried in the
sand. One odor was designated S+, and mice were allowed to dig
and retrieve the chocolate from this container. The other odor
was S-, and both containers were removed immediately if subjects
began to dig in an S- container. After meeting a two-session
acquisition criterion, subjects were given a series of
discrimination reversals. In Experiment 1, 12 Swiss-Webster mice
(6 male and 6 female) acquired the olfactory discrimination in
three to five sessions and completed 3 to 10 successive
discrimination reversals within a 50-session testing limit. In
Experiment 2, subjects were 14 Pahenu2 mice, the mouse
mutant for phenylketonuria; 7 were homozygotes in which the
disorder was expressed (PKU), and 7 were heterozygotes with
normal metabolism (non-PKU). Thirteen mice completed pretraining
in four to seven sessions, acquisition required 3 to 12 sessions,
and all mice completed at least three reversals. Learning rates
were similar in PKU and non-PKU mice. We discuss issues related
to implementation and several potentially useful procedural
variations.
Key words: olfactory discrimination, discrimination reversal,
phenylketonuria, digging, Pahenu2 mice, Swiss-Webster mice,
mice