It is widely accepted that impaired safety learning to a safe stimulus is a pathological feature of anxiety disorders. Safety learning refers to learning that a stimulus is associated with the absence of threat. Cognitive mechanisms that underlie successful threat and safety learning are, however, poorly understood. This study aimed to identify various physiological markers, including neural oscillations and event-related potentials (ERPs) that predict successful threat and safety learning. Therefore, to detect potential differences in these markers, we measured EEG in a fear learning framework combined with a subsequent memory paradigm. Thirty-seven participants were asked to memorize a series of associations between faces and an aversive unconditioned stimulus (US) or its omission. We found a decrease of power in the alpha band in occipital brain regions during learning for both threatening (conditioned stimuli, CS+) and safe faces (control stimuli, CS-) that were subsequently remembered to be associated with a US or not. No effects in theta band were found. In regard to ERPs, a late positive potential (LPP) and a P300 component were larger for remembered than for forgotten CS-US associations. The P300 was also enhanced to remembered US and US omissions, thus replicating previous findings. These results point to the importance of cognitive resource allocation as an underlying mechanism of fear learning and electrophysiological measurements as potential biomarkers for successful threat and safety learning.
Keywords: Alpha frequency; Fear conditioning; Intentional learning; LPP; P300; Subsequent memory effects.
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