therefore, equal numbers of mice received the ethanol unconditioned stimulus in either chamber. Animals were tested at the same time each day (1200) and given a single injection and immediately placed into one chamber for precisely five minutes. Saline and ethanol injections were alternated until a total of six conditioning sessions were achieved for both saline and ethanol (12 conditioning days). A lower 1.75 g/kg dose of ethanol was used because of the hypersensitivity observed in Lwt/+ animals. On the testing day, animals were given access to both chambers for 30 minutes and time spent on each side was recorded [44].
