Table 1.
Schematic Representation of Experimental Procedures
| Training phase |
||||||
|---|---|---|---|---|---|---|
| Group | Lever | Lever training | NIC SA | 30 NIC Baseline | Extinction | Reacquisition |
| 2-Lever | VS | Food | VS | VS | VS | VS |
| 30 NIC (n=9) | SAL/SAL (n=9) | |||||
| Infusion | Food | 60 NIC (n=8) | 30 NIC | SAL/30 NIC | ||
| 90 NIC (n=7) | MEC/30 NIC (n=8) | |||||
| NIC+VS | 30 NIC+VS (n=6) | SAL/SAL+VS (n=8) | ||||
| Active | Food | 60 NIC+VS (n=8) | 30 NIC+VS | SAL/30 NIC+VS | ||
| 90 NIC+VS (n=6) | MEC/30 NIC+VS (n=10) | |||||
| Inactive | Food | — | — | — | — | |
| NIC-Only | 30 NIC+VS (n=8) | SAL/SAL (n=10) | ||||
| Active | Food | 60 NIC+VS (n=6) | 30 NIC+VS | SAL/30 NIC | ||
| 90 NIC+VS (n=8) | MEC/30 NIC (n=9) | |||||
| Inactive | Food | — | — | — | — | |
| VS-Only | VS | Food | VS | VS | VS | VS |
| Infusion | Food | SAL (n=6) | SAL | SAL/SAL (n=3) | SAL/SAL | |
| MEC/SAL (n=3) | ||||||
NIC, /NIC: nicotine infusions available during session; SAL, /SAL: vehicle infusions available during session; VS: visual stimulus; 30, 60, 90: unit nicotine dose (μg/kg/infusion); MEC/, SAL/: mecamylamine or vehicle pretreatment 15min before session; (n=x): number of subjects included in analyses for NIC SA and Baseline–Extinction–Reacquisition phases, chloral hydrate tests determined catheter patency after NIC SA and Reacquisition phases.