Table 1

Statistical analysis for experiments 1–4 (SPSS GLM repeated-measures module)

Figure numberFactor nameF valueP valuePartial Eta2
Repeated-measures ANOVA
With sex as a factor
Food
Sex (male, female), between-subjects
Session (1–6), within-subjects
Sex × Session interaction
Fentanyl
Sex (male, female), between-subjects
Session (1–12), within-subjects
Sex × Session interaction

F(1,12) = 1.0
F(5,60) = 1.1
F(5,60) = 0.1

F(1,12) = 0.7
F(11,132) = 3.7
F(11,132) = 1.4

0.35
0.37
0.99

0.43
<0.001*
0.20

0.07
0.08
0.01

0.05
0.24
0.10
Figure 1C, discrete choice
Repeated-measures ANOVA
With sex as a factor
Preference score
Sex (male, female), between-subjects
Session (1–12), within-subjects
Sex × Session interaction

F(1,12) = 4.8
F(11,132) = 15.4
F(11,132) = 1.0

0.05*
<0.001*
0.45

0.28
0.56
0.08
Figure 1D, relapse test
Total responding
Repeated-measures ANOVA
Without sex as a factor
Lever (active, inactive), within-subjects

F(1,7) = 37.0

<0.001*

0.84
Figure 1D, relapse test
Time course
Repeated-measures ANOVA
Without sex as a factor
Session Time (15, 30, 45, 60), within-subjects
Lever (active, inactive), within-subjects
Session Time × Lever interaction

F(3,21) = 11.1
F(1,7) = 37.0
F(3,21) = 9.6

<0.001*
<0.001*
<0.001*

0.61
0.84
0.58
Figure 1F, Fos neuron counting
Repeated-measures ANOVA
OFC Cnr1: without sex as a factor
Fos
Test Condition (Test, No Test), between-subjects
Cnr1
Test Condition (Test, No Test), between-subjects
Fos+Cnr1
Test Condition (Test, No Test), between-subjects
Pir Cnr1: without sex as a factor
Fos
Test Condition (Test, No Test), between-subjects
Cnr1
Test Condition (Test, No Test), between-subjects
Fos+Cnr1
Test Condition (Test, No Test), between-subjects
OFC Cnr1 and Vgat: without sex as a factor
Cnr1+Vgat
Test Condition (Test, No Test), between-subjects
Fos+Cnr1+Vgat
Test Condition (Test, No Test), between-subjects
OFC Drd1 and Drd2: without sex as a factor
Fos
Test Condition (Test, No Test), between-subjects
Drd1
Test Condition (Test, No Test), between-subjects
Drd2
Test Condition (Test, No Test), between-subjects
Fos+Drd1
Test Condition (Test, No Test), between-subjects
Fos+Drd2
Test Condition (Test, No Test), between-subjects
Pir Drd1 and Drd2: without sex as a factor
Fos
Test Condition (Test, No Test), between-subjects
Drd1
Test Condition (Test, No Test), between-subjects
Drd2
Test Condition (Test, No Test), between-subjects
Fos+Drd1
Test Condition (Test, No Test), between-subjects
Fos+Drd2
Test Condition (Test, No Test), between-subjects

F(1,12) = 10.4

F(1,12) = 2.4

F(1,12) = 11.7

F(1,12) = 5.1

F(1,12) = 0.0

F(1,12) = 1.6

F(1,12) = 0.3

F(1,12) = 6.2

F(1,10) = 5.4

F(1,10) = 2.9

F(1,10) = 1.4

F(1,10) = 1.6

F(1,10) = 2.2

F(1,12) = 7.2

F(1,12) = 0.0

F(1,12) = 1.7

F(1,12) = 5.4

F(1,12) = 1.7

0.007*

0.15

0.005*

0.04*

0.89

0.23

0.57

0.03*

0.04*

0.12

0.27

0.24

0.17

0.02*

0.99

0.22

0.04*

0.22

0.47

0.17

0.49

0.30

0.00

0.12

0.03

0.34

0.35

0.22

0.12

0.14

0.18

0.37

0.00

0.12

0.31

0.13
Repeated-measures ANOVA
With sex as a factor
Food
Sex (male, female), between-subjects
Session (1–6), within-subjects
Sex × Session interaction
Fentanyl
Sex (male, female), between-subjects
Session (1–12), within-subjects
Sex × Session interaction

F(1,44) = 0.2
F(5,220) = 12.4
F(5,220) = 4.6

F(1,44) = 0.8
F(11,484) = 32.0
F(11,484) = 0.7

0.69
<0.001*
<0.001*

0.38
<0.001*
0.74

0.00
0.22
0.10

0.02
0.42
0.02
Figure 2C, discrete choice
Repeated-measures ANOVA
With sex as a factor
Preference score
Sex (male, female), between-subjects
Session (1–12), within-subjects
Sex × Session interaction

F(1,44) = 12.3
F(11,484) = 15.2
F(11,484) = 1.7

0.001*
<0.001*
0.07

0.22
0.26
0.04
Figure 2D, relapse test
Total responding
Mixed ANOVA
With sex as a factor
Sex (male, female), between-subjects
AM251 Dose (0, 0.3, 1 µg), between-subjects
Lever (active, inactive) within-subjects
AM251 Dose × Lever interaction
Sex × AM251 Dose interaction
Sex × Lever interaction
Sex × AM251 Dose × Lever interaction

F(1,40) = 0.0
F(2,40) = 1.0
F(1,40) = 152.7
F(2,40) = 0.9
F(2,40) = 0.3
F(1,40) = 0.0
F(2,40) = 1.2

0.94
0.39
<0.001*
0.43
0.74
0.97
0.31

0.0
0.05
0.79
0.04
0.02
0.0
0.06
Figure 2D, relapse test
Time course
Mixed-ANOVA
Without sex as a factor
AM251 Dose (0, 0.3, 1 µg), between-subjects
Session Hour (1–3) within-subjects
Lever (active, inactive), within-subjects
AM251 Dose × Session Hour interaction
AM251 Dose × Lever interaction
Session Hour × Lever interaction
AM251 Dose × Session Hour × Lever interaction

F(2,43) = 1.1
F(2,86) = 144.2
F(1,43) = 160.4
F(4,86) = 1.8
F(2,43) = 1.0
F(2,86) = 131.5
F(4,86) = 1.4

0.34
<0.001*
<0.001*
0.14
0.39
<0.001*
0.24

0.05
0.77
0.79
0.08
0.04
0.75
0.06
Figure 2E, reacquisition
Mixed-ANOVA
With sex as a factor
Sex (male, female), between-subjects
AM251 Dose (0, 0.3, 1 µg), between-subjects
Session Hour (1–6) within-subjects
AM251 Dose × Session Hour interaction
Sex × AM251 Dose interaction
Sex × Session Hour interaction
Sex × AM251 Dose × Session Hour interaction

F(1,40) = 1.9
F(2,40) = 1.2
F(5,200) = 8.7
F(10,200) = 1.3
F(2,40) = 2.9
F(5,200) = 1.9
F(10,200) = 1.2

0.18
0.30
<0.001*
0.26
0.07
0.10
0.32

0.04
0.06
0.18
0.06
0.13
0.04
0.06
Repeated-measures ANOVA
Without sex as a factor
Food
Session (1–6), within-subjects
Fentanyl
Session (1–12), within-subjects

F(5,50) = 1.5

F(11,110) = 5.3

0.22

<0.001*

0.13

0.35
Figure 3C, discrete choice
Repeated-measures ANOVA
Without sex as a factor
Preference score
Session (1–12), within-subjects

F(11,110) = 2.7

0.004*

0.22
Figure 3D, relapse test
Total responding
Repeated-measures ANOVA
Without sex as a factor (without statistical outlier)
WIN55,212-2 Injection (vehicle, WIN55,212-2), within-subjects
WIN55,212-2 Dose (0.3, 1 µg), between-subjects
Lever (active, inactive) within-subjects
WIN55,212-2 Injection × Dose interaction
WIN55,212-2 Injection × Lever interaction
WIN55,212-2 Dose × Lever interaction
WIN55,212-2 Injection × Dose × Lever interaction

F(1,8) = 0.4
F(1,8) = 0.0
F(1,8) = 38.4
F(1,8) = 0.0
F(1,8) = 0.6
F(1,8) = 0.0
F(1,8) = 0.0

0.57
0.87
<0.001*
0.86
0.46
0.94
0.85

0.04
0.00
0.83
0.00
0.07
0.00
0.00
Figure 3D, relapse test
Total responding
Repeated-measures ANOVA
Without sex as a factor (with statistical outlier)
WIN55,212-2 Injection (vehicle, WIN55,212-2), within-subjects
WIN55,212-2 Dose (0.3, 1 µg), between-subjects
Lever (active, inactive) within-subjects
WIN55,212-2 Injection × Dose interaction
WIN55,212-2 Injection × Lever interaction
WIN55,212-2 Dose × Lever interaction
WIN55,212-2 Injection × Dose × Lever interaction

F(1,9) = 0.1
F(1,9) = 0.6
F(1,9) = 26.5
F(1,9) = 0.7
F(1,9) = 0.1
F(1,9) = 0.5
F(1,9) = 0.8

0.75
0.45
<0.001*
0.42
0.73
0.48
0.40

0.01
0.07
0.75
0.07
0.01
0.06
0.08
Figure 3E, reacquisition
Repeated-measures ANOVA
Without sex as a factor
WIN55,212-2 Injection (vehicle, WIN55,212-2), within-subjects
WIN55,212-2 Dose (0.3, 1 µg), between-subjects
WIN55,212-2 Injection × Dose interaction

F(1,9) = 0.6
F(1,9) = 4.5
F(1,9) = 0.3

0.44
0.06
0.61

0.07
0.33
0.03
Figure 3G, re-training
Repeated-measures ANOVA
Without sex as a factor
Fentanyl
Session (1–4), within-subjects

F(3,30) = 0.2

0.92

0.02
Figure 3H, discrete choice
Repeated-measures ANOVA
Without sex as a factor
Preference score
Session (1–4), within-subjects

F(3,30) = 1.5

0.25

0.13
Repeated-measures ANOVA
With sex as a factor
Food
Sex (male, female), between-subjects
Session (1–6), within-subjects
Sex × Session interaction
Fentanyl
Sex (male, female), between-subjects
Session (1–12), within-subjects
Sex × Session interaction

F(1,18) = 1.3
F(5,90) = 3.9
F(5,90) = 5.8

F(1,18) = 0.0
F(11,198) = 2.9
F(11,198) = 0.5

0.27
0.003*
<0.001*

0.97
0.001*
0.89

0.07
0.18
0.24

0.00
0.14
0.03
Figure 4C, discrete choice
Repeated-measures ANOVA
With sex as a factor
Preference score
Sex (male, female), between-subjects
Session (1–12), within-subjects
Sex × Session interaction

F(1,18) = 0.2
F(11,198) = 5.9
F(11,198) = 1.5

0.66
<0.001*
0.12

0.01
0.25
0.08
Figure 4D, relapse test
Total responding
Repeated-measures ANOVA
Without sex as a factor (without statistical outlier)
SCH39166 Injection (vehicle, SCH39166), within-subjects
SCH39166 Dose (1, 3 µg), between-subjects
Lever (active, inactive) within-subjects
SCH39166 Injection × Dose interaction
SCH39166 Injection × Lever interaction
SCH39166 Dose × Lever interaction
SCH39166 Injection × Dose × Lever interaction

F(1,17) = 0.0
F(1,17) = 0.9
F(1,17) = 130.4
F(1,17) = 0.2
F(1,17) = 0.1
F(1,17) = 4.6
F(1,17) = 0.0

0.86
0.35
<0.001*
0.65
0.82
0.05*
0.93

0.00
0.05
0.89
0.01
0.00
0.21
0.00
Figure 4D, relapse test
Total responding
Repeated-measures ANOVA
Without sex as a factor (with statistical outlier)
SCH39166 Injection (vehicle, SCH39166), within-subjects
SCH39166 Dose (1, 3 µg), between-subjects
Lever (active, inactive) within-subjects
SCH39166 Injection × Dose interaction
SCH39166 Injection × Lever interaction
SCH39166 Dose × Lever interaction
SCH39166 Injection × Dose × Lever interaction

F(1,18) = 0.6
F(1,18) = 0.0
F(1,18) = 44.2
F(1,18) = 0.9
F(1,18) = 0.3
F(1,18) = 0.2
F(1,18) = 0.5

0.46
0.99
<0.001*
0.36
0.61
0.68
0.48

0.03
0.00
0.71
0.05
0.02
0.01
0.03
Figure 4E, reacquisition
Repeated-measures ANOVA
Without sex as a factor
SCH39166 Injection (vehicle, SCH39166), within-subjects
SCH39166 Dose (1, 3 µg), between-subjects
SCH39166 Injection × Dose interaction

F(1,18) = 0.2
F(1,18) = 1.8
F(1,18) = 0.1

0.63
0.20
0.77

0.01
0.09
0.01
Figure 4G, re-training
repeated-measures ANOVA
With sex as a factor
Fentanyl
Sex (male, female), between-subjects
Session (1–2), within-subjects
Sex × Session interaction

F(1,18) = 2.2
F(1,18) = 1.9
F(1,18) = 0.4

0.15
0.19
0.55

0.11
0.09
0.02
Figure 4H, discrete choice
Repeated-measures ANOVA
With sex as a factor
Preference score
Sex (male, female), between-subjects
Session (1–4), within-subjects
Sex × Session interaction

F(1,18) = 3.2
F(3,54) = 0.1
F(3,54) = 0.1

0.09
0.93
0.94

0.15
0.01
0.01
• Partial Eta2 = proportion of explained variance.