Vocalization pattern analysis as a method for classification of emotional states in the common marmosets (Callithrix jacchus)

In order to classify emotional states of animals, common marmosets may be useful subjects. It is well known that there is strong correlation between the patterns of vocalization and the specific behavior in the common marmosets (e.g., \u27chatter\u27 call corresponds aggressive behavior). This suggests that the vocalization patterns of marmosets may be useful to classify emotional states of the animals. Here, we collected vocalization patterns of the marmoset in the isolated environment and tried to map their corresponding emotional states. Two adult common marmosets were used in this study. Each animal was isolated in the novel cage, and habituated for 5 sessions of 60 min long. The vocalization patterns in the first 30 min in each session were analyzed based on producing sonogram. The number of patterns of vocalization decreased as the session progressed, so that they vocalized mainly \u27phee\u27 call, which corresponds \u27calling partners\u27, after habituation. They often vocalized with specific pattern, \u27tsikegg\u27 call (one\u27tsik\u27call followed by a few\u27egg\u27calls) at the first habituation trial. As the sessions of habituation progressed, the number of \u27tsikegg\u27 call declined significantly. This suggests that \u27tsikegg\u27 call reflects anxiety evoked by the novel environment. We applied this vocalization pattern analysis to a methamphetamine (METH) test in the same environment. The number of \u27tsikegg\u27 calls in 30 min significantly increased with METH (2mg/kg) treatment in comparison with the saline treatment, suggesting that METH makes marmoset anxiety. Taken together, vocalization patterns of marmosets may allow us to identify their emotional states with higher validity.Neuroscience 2010, SfN\u27s 40th annual meetin