Table 1.
Results in non-reinforced responding, sucrose and cocaine self-administration (mean ± SEM).
| Spontaneous non-reinforced responding | ||||||
| Total initial lever presses/1 h | Habituation latency (# sessions) | |||||
| Sham (N = 13) | 41.0 ± 7.7 | 2.38± 0.30 | ||||
| Lesioned (N = 11) | 68.7± 22.1 | 4.18± 1.02 | ||||
| Unilateral (N = 5) | 34.8 ± 11.1 | 2.60 ± 1.12 | ||||
| Acquisition of sucrose reinforcement | ||||||
| Acquisition latency (# sessions) | ||||||
| Sham (N = 13) | 6.54 ± 0.78 | |||||
| Lesioned (N = 11) | 4.09 ± 0.28 | |||||
| Unilateral (N = 5) | 6.8 ± 2.11 | |||||
| Extinction from sucrose reinforcement | ||||||
| Initial extinction responding (First session) | ||||||
| Sucrose-paired lever | Inactive lever | Extinction latency (# sessions) | ||||
| Sham (N = 13) | 200.5 ± 21.4 | 45.9 ± 21.7 | 5.46 ± 0.98 | |||
| Lesioned (N = 11) | 174.8 ± 34.5 | 44.9 ± 13.7 | 5.45 ± 1.27 | |||
| Unilateral (N = 4) | 225.8 ± 59.8 | 33.3 ± 14.0 | 10.25 ± 2.75 | |||
| Acquisition of cocaine self-administration | ||||||
| Drug-paired lever responses |
||||||
| Week 1 | Week 2 | Week 3 | Week 4 | |||
| Sham (N = 13) | 36 ± 13.0 | 40.5 ± 9.0 | 34.6 ± 7.0 | 40.8 ± 7.9 | ||
| Lesioned (N = 10) | 102.8± 62.1 | 132.8 ± 36.0 | 69.3 ± 14.0 | 77.2 ± 17.7 | ||
| Unilateral (N = 4) | 2.5 ± 0.7 (N = 2) | 113 ± 107.6 | 57.2 ± 25.1 | 43.6 ± 23.2 | ||
| Acquisition latency (# sessions) (non-acquirers score 21) | Cocaine intake (mg/kg) (Week 4 of acquisition) | Percent of sessions reaching 120 injecton max | ||||
| Sham (N = 13) | 13.6 ± 2.1 | 65.1 ± 10.7 | 1.15 ± 0.8 | |||
| Lesioned (N = 10) | 10.8± 2.2 | 98.4 ± 15.5 | 7.5 ± 3.0 | |||
| Unilateral (N = 4) | 16.3± 2.9 | 68.6 ± 33.7 | 5.0 ± 2.9 | |||
| Extinction from cocaine self-administration | ||||||
| Maintenance cocaine intake before extinction (mg/kg/day) | Initial extinction responding (First sessions) Drug-paired lever | Inactive lever | Extinction latency (# sessions) | |||
| Sham (N = 12) | 88.4 ± 7.9 | 47.8 ± 9.0 | 19.3 ± 6.1 | 2.92 ± 0.26 | ||
| Lesioned (N = 10) | 108.5 ± 15.7 | 87.4 ± 24.0 | 41.4 ± 20.1 | 5.50 ± 1.28 | ||
| Unilateral (N = 3) | 119.5 ± 27.9 | 73.7 ± 19.6 | 17.0 ± 8.3 | 7.33 ± 1.33 | ||
| Cocaine-induced reinstatement | ||||||
| Drug-paired lever responses/ 1 h | ||||||
| Baseline | Saline | Baseline | Coc 5 mg/kg | Baseline | Coc 15 mg/kg | |
| Sham (N = 11) | 2.5 ± 0.8 | 3.9 ± 1.5 | 2.1 ± 1.1 | 16.9 ± 3.6 | 2.3 ± 0.8 | 44.0 ± 10.9 |
| Lesioned (N = 8) | 2.6 ± 1.6 | 2.8 ± 1.0 | 1.9 ± 0.6 | 51.9 ± 11.4 | 2.6 ± 1.7 | 107.6 ± 51.0 |
| Unilateral (N = 3) | (not listed due to high baselines) | |||||