Ventromedial prefrontal cortex activity during extinction recall suggests successful extinction learning via mental imagery.

Mental imagery is an important element of psychological therapies for fear-related disorders. The present study evaluated the efficacy of imagery extinction using a within-subject design allowing for the comparison of a conditioned stimulus extinguished via mental imagery (CS+Ei) to an unextinguished conditioned stimulus (CS+U) during extinction recall. Twenty-eight human participants underwent differential fear conditioning during functional magnetic resonance imagining. Successful acquisition of differential fear conditioning was confirmed by self-reported fear, skin conductance response (SCR), and activation the anterior insula and dorsal anterior cingulate cortex. Next, participants imagined the CS+Ei without mild shock and the CS- during the imagery extinction learning phase, in which fear transfer was confirmed with self-reported fear and SCR. Lastly, all stimuli were again visually presented in the visual extinction recall phase. Significantly greater ventromedial prefrontal cortex (vmPFC) activity was observed for the CS+Ei compared to the CS+U, suggestive of successful extinction recall following imagery extinction. Moreover, a vmPFC seed-based psychophysiological interaction analysis indicated that unlike the CS+Ei, the CS+U was positively connected with bilateral amygdala during extinction recall. The present study highlights dissociable vmPFC involvement during extinction recall when viewing the CS+Ei following fear extinction using mental imagery as compared to the unextinguished CS+.