“…One week after completing the saline or amphetamine treatment regimens, different cohorts of mice were rapidly decapitated, and their brains were flash‐frozen in 2‐methylbutane (Fisher Scientific, Hampton, New Hampshire) chilled with dry ice. Bilateral punches of the VTA, NAcc, and PFC were excised from 1‐mm thick coronal slices starting from sections corresponding to plate 55 (−2.92 mm, anterior/posterior relative to Bregma) and 15 (1.94 mm, anterior/posterior relative to Bregma), respectively, of Paxinos and Franklin and processed for western blot as before . Briefly, protein samples (15 μg) were separated on a 10% SDS‐PAGE and transferred to a nitrocellulose membrane that was incubated overnight at 4°C with antibodies against DCC (1:1000, Cat#554223, BD Pharmingen, Mississauga, ON, Canada), Netrin‐1 (1:750 dilution, Cat#NB100‐1605, Novus Biologicals, Littleton, Colorado) and β‐actin (1:15000, Sigma‐Aldrich, Oakville, ON, Canada).…”