Table 1.

Average responses on the active lever and inactive lever during the last 4 days of an FR5 schedule and PR schedule for each group

Group	Fixed ratio scheduled (FR5)			Progressive ratio schedule
	Active lever	Inactive lever	Time-out responding	Active lever	Inactive lever
Contingent NIC + VS (0.01 mg/kg per infusion), n=9	83.42±10.17	2.22±0.45	11.47±1.52	106.22±10.94	1.83±0.34
Noncontingent NI + VS (0.01 mg/kg per infusion), n=11	78.39±8.97	2.50±0.38	13.50±2.00	95.34±6.12	2.34±0.32
Contingent NIC + VS (0.03 mg/kg per infusion), n=8	57.66±7.41	3.50±0.76	10.78±1.49	131.66±14.55	2.88±0.59
Noncontingent NIC + VS (0.03 mg/kg per infusion), n=11	62.93±4.82	3.68±0.50	7.80±0.77	98.60±10.90	3.38±0.39
Contingent NIC + VS (0.09 mg/kg per infusion), n=10	54.23±4.19	1.20±0.29	5.85±0.90	122.78±14.79	4.43±0.88
Noncontingent NIC + VS (0.09 mg/kg per infusion), n=11	67.75±6.73	2.82±0.51	9.34±1.07	158.91±15.46	4.39±0.62
Contingent SAL + VS, n=8	24.88±3.30	1.38±0.30	5.19±0.75	42.59±6.75	2.81±0.54
Contingent SAL + no VS, n=9	5.25±0.81	1.78±0.36	2.33±0.42	8.44±1.49	3.00±0.69
Contingent NIC + no VS (0.01 mg/kg per infusion), n=6	3.79±0.66	1.25±0.53	2.13±0.36	8.63±2.41	2.33±0.51
Contingent NIC + no VS (0.03 mg/kg per infusion), n=6	2.71±0.38	1.38±0.77	1.46±0.29	5.38±1.27	2.08±0.58
Contingent NIC + no VS (0.09 mg/kg per infusion), n=6	38.67±7.91	4.63±0.97	13.04±2.85	127.13±33.10	17.25±5.27

The average responding during the 1-min time-out period after each reinforcer delivery is also indicated for the last 4 days of an FR5 schedule