A New Automated Method to Estimate the Behavioral Response of a Small Animal Using a Multicolor Detection Technique

A new automated method to estimate the behavioral response of a small animal was developed using a multicolor detection technique. Two color markers were preliminarily applied to rats - yellow dye on the mouth and fluorescent green tape on the right hind paw. Behaviors of the animals were recorded in dual mode, from both above and below the subject, by two digital video cameras. Dual mode image processing proved approximately 20% more effective than single mode. To check errors of color discrimination principal component analysis and cluster analyses were performed, and the results demonstrated that these two colors were well discriminated and classified, predominantly by differences of the red component in these colors. A typical biphasic response of licking behavior induced by formalin was observed when the color range was set within appropriate limits. This technique has the potential to measure not only simple locomotor activity but also more elaborate behaviors such as flinching, biting or licking with high spatial and temporal resolution.