Summary of behavioral procedures
| Novel stimuli | Habituation | Conditioned fear | ||
|---|---|---|---|---|
| Day 1 | A.M. | BOX (N) | BOX (N) | BOX (N) |
| Day 2 | A.M. | BOX (N) | BOX (T & L) | BOX (T, L & S)1_a |
| P.M. | BOX (N) | BOX (T & L) | BOX (N) | |
| Day 3 | A.M. | BOX (N) | BOX (T & L) | BOX (N) |
| P.M. | BOX (N) | BOX (N) | BOX (T, L & S)1_b | |
| Day 4 | A.M. | BOX (N) | BOX (T & L) | BOX (N) |
| P.M. | BOX (N) | BOX (N) | BOX (N) | |
| Day 5 | A.M. | BOX (N) | BOX (N) | BOX (N) |
| P.M. | BOX (N) | BOX (T & L) | BOX (T, L & S)1_b | |
| Day 6 | A.M. | BOX (N) | BOX (N) | BOX (T, L & S)1_b |
| P.M. | BOX (N) | BOX (N) | BOX (T, L & S)1_b | |
| Day 7 | A.M. | Surgery | Surgery | Surgery |
| Day 8 | A.M. | BOX (N) | BOX (T & L) | BOX (N) |
| P.M. | BOX (N) | BOX (N) | BOX (T, L & S)1_b | |
| Day 9 | A.M. | Microdialysis | Microdialysis | Microdialysis |
On days 2–6 and day 8, the order of presentation of S− (N, Habituation group and Conditioned fear) and of S+ sessions (T & L, Habituation group; T, L & S, Conditioned fear group) was randomized for each rat. (N), No tone or light stimuli; (T & L), tone and light; (T, L & S), tone, light and shock.
↵F1_a (T, L & S), Shock sessions were: 1st FR1, 2nd FR2, 3rd and 4th VR3.
↵F1_b (T, L & S), Shock sessions were: one FR1 and three VR3, in random order.