Phm 110

Standard operant conditioning chambers (28 × 21 × 21 cm; ENV-001; MED Associates, St. Albans, VT) with alternating aluminum and Plexiglas walls including a metal rod floor were located inside sound-attenuating chambers (ENV-018M; MED Associates, St. Albans, VT). A recessed food tray (5 × 4.2 cm) was located 2 cm above the floor in the center of one of the aluminum walls, and a response lever was located 6 cm above the floor on each side of the food tray. A white stimulus light (28 v, 3 cm diameter) was located 6 cm above each lever. The standard operant chambers were retrofitted with a counterbalance arm, swivel, and leash (PHM-110, PHM-115I and PHM-120A, respectively; MED Associates, St. Albans, VT). Drug infusions were delivered via a MED Associates infusion pump located outside of the sound-attenuating chamber (PHM-100; MED Associates, St Albans, VT). Responses were recorded and programmed consequences were controlled by a computer in an adjacent room equipped with Med-PC software (Med Associates, St. Albans, VT).

Standard operant conditioning chambers (28 × 21 × 21 cm; ENV-001; MED Associates, St. Albans, VT) with alternating aluminum and Plexiglas walls including a metal rod floor were located inside sound-attenuating chambers (ENV-018M; MED Associates, St. Albans, VT) were used in both d-amphetamine and food self-administration sessions. A recessed food tray (5 × 4.2 cm) was located 2 cm above the floor in the center of one of the aluminum walls, and a response lever was located 6 cm above the floor on each side of the food tray. A white stimulus light (28 v; 3 cm diameter) was located 6 cm above each lever. The standard operant chambers were retro-fitted with a counterbalance arm, swivel, and leash (PHM-110, PHM-115I and PHM-120A, respectively; MED Associates, St. Albans, VT). Drug infusions were delivered via a MED Associates infusion pump located outside of the sound-attenuating chamber (PHM-100; MED Associates, St Albans, VT). Responses were recorded and programmed consequences were controlled by a computer in an adjacent room equipped with Med-PC software (Med Associates, St. Albans, VT).