Acclimation & testing periods
Mice were obtained from The Jackson Laboratory JAX® (Bar Harbor, ME) at 4-7wks of age. Male inbred NMRI and 129S6/SvEvTac mice were obtained from B & K Universal (Grimston, Hull, East Yorkshire, UK) and Taconic (Germantown, NY). They were identified by ear notching at 4–7wks of age, and allowed to adapt to their new housing conditions for at least 1 week before testing. 5–10 wks of age Available ad libitum Available ad libitum All mice of the same strain and sex are housed in groups of five The animals were maintained under 12h-light/12h-dark cycle with lights on at 6:00 am. Mice were tested individually during the light cycles between 11:00 am and 5:00 pm at 8–9wks of age. All animals were brought to the testing room at least 1 hr before the commencement of each behavioral test, and remained in the same room throughout the test 21.3 - 23.4°C All experiments followed the National Institutes of Health Guide for Care and Use of Laboratory Animals and were approved by the local institutional review committee