Figure 1. Intra-NAc shell microinjection of d-amphetamine in AM and PM fed rats.
D-amphetamine was microinjected bilaterally in the NAc shell of AM-fed (filled circles) and PM-fed (open circles) food-restricted rats. Shown are mean ±SEM percent change in two measures of reward threshold, M-50 (top panel) and X-intercept (middle panel), as a function of dose. Percent change in the maximum reinforcement rate (bottom panel) is also shown. *p<0.05, ***p<0.001 compared to the 0.0 (vehicle) dose.