Mice were habituated to an open field (50x50cm; illuminated at 30 lux) for 30 minutes, after which they received an injection of d-amphetamine (2 mg/kg i.p.), cocaine (10 mg/kg s.c.), GBR12909 (16 mg/kg i.p.), or MK-801 (0.3 mg/kg i.p.) (Sigma-Aldrich, St. Louis, MO) and were returned to the open field for an additional 45 (d-amphetamine and cocaine) or 90 (GBR12909 and MK-801) minutes. Doses and route of administration were based on those established previously in the literature as resulting in a moderate hyperlocomotor response, in order to allow a further increase to be possible without inducing stereotypic behaviors. (Hirabayashi et al., 1991 (link), Liljequist et al., 1991 (link), Mcnamara et al., 2006 (link), Young et al., 2010 (link)). All compounds were dissolved in 0.9% saline on the day of testing. Distance travelled was assessed using TopScan tracking software (CleverSys, Inc., Reston, VA, USA).