Acute Effects of Estradiol Administration on Brain Function During Fear Learning

Estrogen has been shown to modulate the function of brain regions involved in fear processing, including the amygdala, hippocampus, and ventromedial prefrontal cortex. During fMRI, participants will complete a fear conditioning and generalization task to measure brain activity. They will view different neutral images of geometric shapes which may or may not predict the imminent receipt of an electric shock to the ankle. Across voxels of the brain, activation estimates (BOLD response) will be extracted for CS+ (conditioned threat) vs. CS- (conditioned safety) cues, and linear activation patterns across ambiguous generalization stimuli (i.e., GSs; CS+ > GS1 > GS2 > GS3 > CS-).

Sweat glands activate under stress, increasing the electrical conductance of the skin. Participants will have electrodes attached on their palm to measure changes in sympathetic nervous system activity, providing an objective, physiological measure of anticipatory anxiety.

Self-report can be used to ascertain subjective fear and explicit knowledge of threat contingencies. Participants will be asked to rate of perceived risk of each displayed stimulus from 1 (no risk) to 3 (high risk), contingency learning, and aversiveness of the stimulation (1-5) during task completion in the scanner and after.