(d).

Drugs	Photocell beam breaks ± SEM (60 min)
Vehicle	555.15 ± 48.12
AM 251 (0.25 mg/kg)	406.0 ± 60.29
AM 251 (0.5 mg/kg)	394.71 ± 24.43
AM 251 (1.0 mg/kg)	445.54 ± 42.07
AM 251 (3.0 mg/kg)	517.5 ± 40.66