Behavioral profile of mice with impaired cognition in the elevated plus-maze due to a deficiency in neural cell...

The elevated plus-maze (EPM) test is one of the most used tests for screening levels of anxiety in rodents. In the present study, we studied how impaired cognition due to a deficiency in the neural cell adhesion molecule (NCAM) could affect the behavior of mice in the EPM task. NCAM-knockout mice demonstrated impaired learning in both object-recognition and fear-conditioning tasks. Analysis of the behavior of mice in the EPM task using a minute-by-minute method revealed a profound influence of genotype. Wild-type mice demonstrated quick learning of the aversive properties of the open arms during the first few minutes of a single EPM task, whereas NCAM-/- mice were unable to learn the aversive properties of the open arms of EPM. Wild-type mice also demonstrated habituation to the EPM task in a test/retest paradigm whereas NCAM-knockout mice failed to habituate during the second EPM presentation. Our data show that the anxiolytic-like behavior of NCAM-knockout mice is not just related to levels of innate anxiety but also to their inability to recognize potential danger associated with the open arms of the EPM task.