PSAP schedule of puzzles
| Session | First response series | Second response series |
|---|---|---|
| 1 | 1 nose poke | – |
| 2 | 1 seeking lever | – |
| 3 | 1 wheel turn | – |
| 4 | 1 nose poke | 1 seeking lever |
| 5 | 1 wheel turn | 1 nose poke |
| 6 | 1 seeking lever | 1 wheel turn |
| 7 | 3 wheel turns | 2 seeking lever |
| 8 | 2 nose pokes | 3 seeking lever |
| 9 | 4 wheel turns | 1 nose poke |
| 10 | 2 seeking lever | 2 wheel turns |
| 11 | 1 nose poke | 2 seeking lever |
| 12 | 4 wheel turns | 1 seeking lever |
| 13 | 2 seeking lever | 2 nose pokes |
| 14 | 3 nose pokes | 2 wheel turns |
| 15 | 4 seeking lever | 2 wheel turns |
| 16 | 3 wheel turns | 3 nose pokes |
| 17 | 3 seeking lever | 2 nose pokes |
| 18 | 4 nose pokes | 2 wheel turns |
| 19 | 3 wheel turns | 3 seeking lever |
| 20 | 4 seeking lever | 1 Nose Poke |
| 21 | 2 nose pokes | 4 wheel turns |
| 22 | 2 wheel turns | 2 seeking lever |
| 23 | 2 seeking lever | 3 nose pokes |
| 24 | 4 wheel turns | 2 nose pokes |
| 25 | 1 seeking lever | 2 wheel turns |
| 26 | 2 nose pokes | 2 seeking lever |
| 27 | 2 wheel turns | 3 nose pokes |
| 28 | 3 nose pokes | 3 wheel turns |
All puzzles used during PSAP are shown. The first 20 puzzles were used during the initial PSAP/IntA procedure. Puzzles 21–28 were used for 2 d blocks between tests of drug seeking and motivation for drug (Fig. 1). A single puzzle was tested each day, with 10 trials per day (or after 7 h had elapsed).