Figure 3.

Amphetamine sensitization. Decreasing activity of mPFC afferents to NAc alters the development of amphetamine sensitization. CNO-mediated activation of hM₄Di in corticostriatal afferents significantly decreased locomotor sensitization to amphetamine as measured by crossovers (a, *P<0.05 versus GFP group), but had no effect on stereotypy ratings (b). Decreasing activity of mPFC afferents to NAc during the induction phase of sensitization significantly increased conditioned responding as measured by crossovers during a saline challenge (c, *P<0.05 versus hM₄Di group given saline during the induction phase), but had no effect on the persistence of locomotor sensitization as measured by crossovers during a low-dose amphetamine challenge (0.5 mg/kg, i.p.) in the absence of CNO pretreatment (d, *P<0.05 versus respective control groups given saline during the induction phase). Data represent mean±SEM. Black symbols/shading (hM₄Di) and white symbols/shading (GFP) represent groups that received amphetamine treatment during the induction phase. Dark gray symbols/shading (hM₄Di) and light gray symbols/shading (GFP) represent groups that received saline treatment during the induction phase. S: saline during the induction phase, A: amphetamine during the induction phase. N=11–17/group.