Older adults recruit dorsomedial prefrontal cortex to decrease negativity during retrieval of emotionally complex real-world events

Recent research from our lab has highlighted a prefrontally-mediated control mechanism that decreases the subjective richness of negative episodic events during older adults' episodic memory retrieval. The current study examined whether such a mechanism was also engaged during retrieval of real-world negative events. In a scanned autobiographical memory task, 56 participants (ages 18-83) were presented with images associated with the 2013 Boston Marathon Bombings. Images fell into three categories: primarily positive, primarily negative, and mixed-valence. Participants retrieved a personal memory associated with each image, elaborated on that memory in as much detail as possible, and rated memory positivity and memory negativity. Unlike in recent episodic memory studies, young and older adults did not differ in how prefrontal regions contributed to retrieval of autobiographical memories associated with primarily negative images. However, there was an age-related reversal in the role of dorsomedial prefrontal recruitment during retrieval of autobiographical memories associated with mixed-valence images: Activity was associated with increased negativity ratings in young adults and decreased negativity in older adults. These findings are the first evidence that older adults engage a prefrontally-mediated mechanism at the time of retrieval to reduce the negativity of memories for real-world emotional events, and further suggest that they may only do so in the case of emotional ambiguity. Such a mechanism could have important implications for understanding how older adults may respond to and evaluate negative events in their daily lives.