DISSECTING THE NEURAL MECHANISMS UNDERLYING NATURALISTIC FEAR EXTINCTION IN MICE

Fear-related experiences often generate strong and enduring emotional memories. Exposure to cues associated with a threat can trigger the retrieval of these memories. However, repeated exposure to these reminder cues can attenuate them through a process known as fear extinction. Strong traumatic experiences may generate memories that are not easily extinguished, and can degenerate into pathological conditions like post-traumatic stress disorders. While fear extinction has been extensively studied using electric foot shock paradigms, less is known about the extinction of more naturalistic forms of fear. In the present study we aim to study fear extinction of more naturalistic fear memories. These arises from exposure to ethologically relevant stimuli such as predators, or aggressive conspecifics. We developed a behavioral paradigm to investigate the extinction of predator- and social-induced fear memories in mice, in comparison with the more classically used electric foot shock. Our results demonstrate that all threat types produce robust fear memories, yet they differ markedly in their extinction dynamics. Future experiments will aim to investigate, at whole-brain level, which brain regions are involved in the extinction of different types of fear using immediate early gene c-Fos. This approach will help clarify the mechanisms underlying extinction of ethological fear memory and may pave the way to rescuing extinction mechanism in particularly strong and difficult-to-overcome social trauma.