Fig. 3
From: Chronic opioid pretreatment potentiates the sensitization of fear learning by trauma
Chronic opioid pretreatment potentiates trauma-induced changes in fear learning and not fear expression. a Experiment schematic. Chronic morphine and a week of drug cessation were given in-between the trauma and the rest of the SEFL procedure. b Morphine-treated animals do not display altered fear of the trauma context when placed back into it, demonstrating that morphine administration does not increase fear expression. c Morphine-treated animals display a trend toward heightened fear in the SEFL test, but this did not reach significance. Dashed line in c reflects average pre-shock baseline freezing on the previous day. Error bars reflect standard error of the mean. N = 18–19/group
