Validation of an automated system for measuring anxiety-related behaviours in the elevated plus maze.

The elevated plus maze (EPM) is one of the most widely used and established tests to assess anxiety-related behaviours and has been validated for use in both mice and rats. Although relatively quick and simple to conduct, there always exists the potential for observer bias during data collection. The KinderScientific EPM system uses a series of apparatus-embedded photobeams to collect spatiotemporal measures such as the amount of time spent in each zone of the maze (centre, open and closed arms), and the frequency of arm entries. Risk assessment behaviours, such as head dips and protected stretches, are also measured which represents a unique feature of this system over other automated EPM systems. We compared observer derived spatiotemporal and risk assessment measurements with automated generated data to test the reliability and accuracy of the automated system. Data were manually collected using different zone entry/exit criteria (2 vs. 4 paws). Automated data were generated using both the default zone map provided with the system and a user-modified zone map. We show that the automated EPM provides accurate and reliable measurements of both spatiotemporal and risk assessment behaviours. In addition, we show that the default zone map overestimated visually observed arm entries while our modified zone map generated data comparable to manually generated data using a 4 paws open arm entry criteria which is most consistently used to define arm entry in the literature. The KinderScientific automated EPM system represents a reliable tool for collection of a wide range of anxiety-related behavioural measures. Copyright 2010 Elsevier B.V. All rights reserved.