Table 1

Mean response rates for cocaine self-administration in individual subjects

Subject	Cocaine Dose (mg/injection)
Subject	0.1	0.3
S-124	3.60	2.00
S-125	0.75	1.14
S-126	2.01	0.65
S-127	0.94	0.92
S-129	0.72	0.71
S-136	0.32	0.89
S-140	0.32	0.72
Mean (±S.E.M.)	1.23 ± 0.48	1.00 ± 0.19

Mean response rates (responses/second) are reported for individual subjects during the last ten sessions of each condition. Data are shown for the two unit doses of cocaine used in drug interaction studies. The doses were selected based on their effectiveness in maintaining peak rates of responding.