Sex differences in fear perception and processing in PTSD – an fMRI study

Abstract

Fifty-six subjects, including 23 men (41.4%) (11 PTSD (47.8%) and 12 TE-HCs (52.2%) - mean age 41 years) and 33 women (58.9%) (20 PTSD (60.6%) and 13 TE-HCs (39.4%) - mean age 34.5 years) participated in the study thus far. The groups underwent a 2-day aversive conditioning and task (7). SCR was acquired throughout the paradigm to verify conditioning and extinction, and to quantify recall deficits. During Conditioning on Day 1, subjects were conditioned to two conditioned stimuli (CS+: red and blue lights) that were paired with an aversive unconditioned stimulus (US), a mild electric shock (60% reinforcement rate), in the fear context; a third light (yellow) was also presented but never followed by a shock (CS-). During Extinction training on Day 1, only one of the two CS+'s was presented and these presentations were all without the US (extinguishing the conditioned to this CS+), in the safe context. On Day 2, recall of the memory was tested when the three lights (1, the extinguished CS+ (CS+E); 2, the CS+ that was not extinguished (CS +NE); and 3, the CS-) were each presented in the safe context. The level of recall of the memory (i.e., extinction recall magnitude) was quantified as the mean SCR for the first four CS+NE trials minus the mean SCR for the first four CS+E trials during recall . !