Fig 1.
Schematic of experimental paradigm.
In the habituation phase on Day 1, stimuli (i.e., lamp “turning on” to show one of three colors) were presented across the two contexts (A). In the conditioning phase on Day 1 (B), the color of the lamp light served as a conditioned Stimulus. Three lights were presented randomized and counterbalanced across participants. Two lights were paired with shock at a 62.5% reinforcement rate and served as the conditioned stimuli that either underwent extinction on Day 2 (CS+E) or remained unextinguished until Day 3 (CS+U). A third color, never paired with shock, provided a reference for differential conditioning (CS-). In the extinction phase on Day 2 (C), the CS+E and CS- were presented without shock in a different (safe) context. One hour prior to extinction, participants took either DCS or PBO. In the recall (D) and renewal (E) phases on Day 3, all three stimuli were presented without shock to test between-session extinction retention and generalization of extinction to the threat context, respectively.
Fig 2.
Conditioned skin conductance responses (SCR) across all phases of the experiment.
Note. DCS was administered 1 hour prior to extinction. PBO = placebo group, DCS = d-cycloserine, SCR = skin conductance response, SE = 1 standard error, CS- = stimulus that was not paired with shock, CS+E = stimulus that was paired with shock during conditioning and presented in the extinction phase, CS+U = stimulus that was paired with shock during conditioning but not presented in the extinction phase.
Table 1.
SCR results from ANOVAs across experimental phases.
Fig 3.
Expectancy of shock (US expectancy) following first and last presentation of different conditioned stimuli, across experimental phases.
Note. Ratings were made retrospectively (i.e. after phase concluded). PBO = placebo group, DCS = d-cycloserine, SCR = skin conductance response, SE = 1 standard error, CS- = stimulus that was not paired with shock, CS+E = stimulus that was paired with shock during conditioning and presented in the extinction phase, CS+U = stimulus that was paired with shock during conditioning but not presented in the extinction phase.
Table 2.
US expectancy results from ANOVAs across experimental phases.