Fig. 1.

Threat conditioning and extinction paradigm. Threat conditioning occurred on Day 1 in context A by pairing a mild shock (unconditioned stimulus) to the lamp light colors pink and blue (termed conditioned stimuli or CS+), but not yellow (termed non-conditioned stimulus or CS-). THC (dronabinol 7.5 mg) or placebo was administered 2-h before threat extinction learning on Day-2, where one CS+ (pink light, now termed extinguished CS+ or CSE) and the CS− are shown in context B. Extinction memory retention was tested one day (Day 3) and one week (Day 10) after extinction learning, where both CS+s (pink light, CSE and the blue light, now termed unextinguished CS+ or CSU) and the CS− are shown