Habituation-dishabituation tests

The principal benefits of the habituation-dishabituation test arise from the speed of testing and the minimal need for equipment. Each animal may complete a nine trial session in less then 30 minutes. An additional advantage comes with the sequential presentation of the stimuli as this methodology avoids the problems associated with the mixing of vapours from different odour stimuli if the odours are presented simultaneously. The test is particularly well suited for field work as the stimuli may be presented on a substrate that the subject normally investigates, thus elicting a more natural response than one might encounter in a lab environment. 

In both the mate choice studies (where mating is prevented) and the habituation-dishabituation test, investigation of an odour source is measured as the behavioural response. However, little attention is usually paid to the functional meaning of investigation in these contexts. We believe that investigation is of limited value in studies of individual recognition, because it is not a specific functional response. 

Habituation-dishabituation tests are based on the premise that successive presentations of a stimulus odor to a subject result in habituation of the behavioral response to that odor (Schellinck Brown 1995). Subjects will respond, however, to a different or novel odor. A change in behavior indicates that the second odor can be discriminated from the first. Lack of response is sometimes taken to indicate a lack of discrimination. However, as we have discussed previously, the failure to display an unlearned response can not be taken as certain evidence against either recognition or discrimination. 

We collected the odors of MHC-congenic rats ( PVG PVG.Rl) maintained on a standard lab chow (Purina) or on a test diet designed to prevent the growth of caecal bacteria (Teklad TD 69466). Rats tested in the habituation-dishabituation task could discriminate between the urinary odors of genetically identical rats after the change from Purina to... 

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