Recent work in our laboratory has employed in vivo microdialysis in freely moving mice to investigate effects of chronic alcohol treatment and withdrawal (early and prolonged) periods on brain corticosterone concentrations by simultaneously measuring time-course evolution of corticosterone concentration in the medial PFC and dorsal HPC seen before, during, and after completion of a working memory task in a T-maze (31, 47). This task is based on spontaneous alternation behavior, known to require intact connections between the two structures for successful performance (48, 49). Specifically, alternation behavior is the innate tendency of rodents to alternate at each successive trial the choice of the goal arm over a series of trials run in a T-maze (except for the first trial). From trial to trial, accurate performance at a given trial (N) requires for subjects to be able to discriminate the specific target trial N − 1 from the interfering trial N − 2. Thus, the target information required for successful performance varies from trial to trial, so that the subject is not only required to temporarily keep specific information in short-term
