Contextual olfactory learning in cockroaches

We investigated the capability of context-dependent olfactory learning in cockroaches. One group of cockroaches received training to associate peppermint odor (conditioning stimulus) with sucrose solution (appetitive unconditioned stimulus) and vanilla odor with saline solution under illumination and to associate peppermint with aversive unconditioned stimulus and vanilla with appetitive unconditioned stimulus in the dark. Another group received training with the opposite stimulus arrangement. Before training, both groups exhibited preference for vanilla over peppermint. After training, the former group preferred peppermint over vanilla under illumination but preferred vanilla over peppermint in the dark, and the latter group exhibited the opposite odor preference. We conclude that cockroaches are capable of disambiguating the meaning of conditioning stimuli according to visual context.