A/Prof Vincent Laurent (UNSW)

Cholinergic regulation of fear by the basal forebrain

Abstract

The basolateral amygdala (BLA) and the infralimbic (IL) region of the medial prefrontal cortex are heavily implicated in fear regulation. These two regions receive dense cholinergic projections from the nucleus basalis of Meynert (NBM) and/or the horizontal limb of the diagonal band of Broca (HDB), which are both located in the basal forebrain. The present experiments examined whether these projections regulate the formation and extinction of fear memories, as well as the capacity of these memories to renew when context cues are manipulated. This was achieved by employing a Pavlovian fear protocol and optogenetics in transgenic rats. Silencing NBM-to-BLA cholinergic projections during fear conditioning weakened the fear memory produced by this conditioning and eliminated its renewal after extinction. A similar outcome was obtained when silencing HDB-to-BLA or HDB-to-IL cholinergic projections during extinction. These findings indicate that basal forebrain cholinergic signalling in the BLA and IL plays a critical role in fear regulation by promoting strength and durability of fear memories. This leads to the proposal that the function of basal forebrain cholinergic signalling is to protect fear memories from erasure when they are extinguished.

Bio

Vincent Laurent is an Associate Professor and ARC Future Fellow in the School of Psychology at the University of New South Wales. His general field of research is behavioural neuroscience, and he is interested in understanding how we learn about environmental stimuli that predict aversive or appetitive events, how the predictive relationships between these stimuli and events are updated when circumstances change, and how they are used to inform our choices and decisions.  His work combines behavioural tasks in rodents and modern neuroscience tools to manipulate specific brain regions and neuronal populations.