Distinct brain networks for remote episodic memory depending on content and emotional value

Abstract

The mechanisms that underlie the storage of old nontraumatic episodic memories remain enigmatic because of the difficulty in modelling this particular type of memory in humans and animals. Episodic memories combine incidental and occasional What-Where-When/In which context multisensory information and can be stored for long periods of time. Here, using a task in rodents that models human episodic memory, including odour/place/context components, we applied advanced behavioural and computational analyses and brain imaging of c-Fos and Zif268 to characterize remote episodic memories and their engrams for the first time. We show that the content and accuracy of memories vary across individuals and depend on the emotional relationship with odours experienced during episodes. Activated brain networks reflect the nature and content of remote episodic memories and their transformation over time, and emotional cortico-hippocampal networks play critical roles in maintaining vivid memories.

Psilocybin-enhanced fear extinction linked to bidirectional modulation of cortical ensembles

“…Subsequent improvements in functional connectivity between the posterior cingulate and prefrontal cortex predict psilocybin-induced enhancements in cognitive flexibility 20 . Importantly, the RSC is involved in the retrieval of remote fear memories, positioning it as a potential substrate for psilocybin's longer-lasting effects [62][63][64][65][66] .…”

“…In mice, Kwapis et al found that TFC extinction depends on excitatory activity in the RSC 68 . Others have shown that optical, electrolytic, and pharmacological interventions in the RSC impact various kinds and stages of FC 45,49,50,55,[63][64][65][66][67][68][69][70][71] . In a one-day paradigm, psilocybin administered 24 hours prior facilitated TFC extinction at low doses 72 .…”