Understanding the neural mechanism of successful navigation involves the investigation of accurate and experience-dependent sensory processing (e.g. Cooper, Miya & Mizumori, 1998; Cooper, Manka, & Mizumori, 2001; Mizumori & Smith, 2006), appropriate regulation of motivational states and outcome evaluation (e.g. Gill & Mizumori, 2008; Puryear & Mizumori, 2009; Kim, Mizumori, & Bernstein, 2010; Mizumori, Yeshenko, Gill, & Davis, 2004; Puryear, Kim & Mizumori 2010), and flexible response selection (e.g. Mizumori, Pratt, Cooper & Guazzelli , 2002; Ragazzino, Ragozzino, Mizumori, & Kesner, 2002; Mizumori, Yeshenko, Gill, & Davis, 2004; Yeshenko, Guazzelli, & Mizumori, 2004; Mizumori, Puryear, Gill, & Guazzelli, 2005). All of these factors likely determine critical decisions that are made during navigation (e.g. Mizumori, Cooper, Leutgeb, & Pratt, 2000; Mizumori, Yeshenko, Gill, & Davis, 2004; Mizumori, Smith, & Puryear, 2007; Gill & Mizumori, 2008). Current research investigates the latter hypothesis by studying the modulatory effect of the midbrain dopamine system on context-dependent neural representation, spatial behaviors, and decisions that animals make during active navigation through novel and familiar environments.