Factor analysis of elevated plus-maze behavior in adolescent and adult rats

The elevated plus-maze (EPM) is among the most popular behavioral models of anxiety. While numerous experiments have validated this test hormonally, pharmacologically, and with factor analysis in adult rodents, few studies have explored use of the EPM to examine ontogenetic differences in anxiety. Given the growing interest in adolescence and the mixed findings to date regarding age-related differences in anxiety, validation of the EPM model for use in adolescence is important. Therefore, the present experiment employed factor analysis to examine underlying EPM behavioral components in adolescent and adult male and female Sprague-Dawley rats across three separate data sets. Results of the analyses conducted across both age and sex produced a 3-factor solution, with the primary component of EPM behavior consisting of anxiety-related behaviors in both adolescent and adult males and females. Within the age analyses, the second and third factors were comprised largely of activity- and risk-related behaviors, respectively. Sex analyses revealed a similar pattern in females, with some behaviors comprising the second and third factors reversed in males. Taken together these results confirm use of the EPM in adolescent and adult rats and demonstrate slight differences in the underlying components of EPM behavior in males versus females.

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