Table 1.

Slope Values Represent the Means for the Descending Linear Slope of Log-Transformed Doses.

Drug	Slope	ED50mg/kg	Maximal % Reduction
METH	−50.23	0.20: UL = .45, LL = 0.004	−21.11
α-PVP	−46.70	0.35: UL = 0.82, LL = 0.023	−25.76
4-MEC	−21.12	6.41: UL = 9.23, LL = 4.37	−17.40
MDPV	−96.07	0.35: UL = 0.55, LL = 0.17	−42.03
Methylone	−17.59	1.00: UL = 1.51, LL = 0.58	−21.50

ED₅₀ values represent the mean dose leading to 50% maximal response with upper 95% confidence limits (UL) and lower 95% confidence limits (LL). Maximal response values represent the mean maximum intracranial self-stimulation (ICSS) threshold reduction (independent of dose)±95% confidence intervals. Results reported for methylenedioxypyrovalerone (MDPV) and methylone were obtained from previous publications (Watterson et al., 2012, 2014).