Grant: Canada Research Chairs

The drive to understand the behavioural and neural processes that support memory have been at the forefront of behavioural and neural science for decades. By uncovering how the brain acquires and stores memories under normal conditions, the field is well-posed to tackle the difficult task of understanding how memory goes awry in disease. While fundamental advances have been made in this regard, progress has been limited to memories acquired through contiguous presentations of stimuli in the environment. As a result, the neural processes that support integration of information across time remain largely underexplored. Specifically, emotional memories can propagate across the an existing and ever changing memory network, linking past and future experiences. The present program of research will focus on understanding the neurobiological substrates of memory propagation. The process of memory propagation will be studied using two well-established behavioural tasks, namely sensory preconditioning and second-order conditioning. In the sensory preconditioning, newly acquired emotional memories are linked to previously learned information, that is, retrospective propagation. In second-order conditioning, previously acquired emotional memories are linked to newly learned information, that is prospective propagation. The proposed research program will examine the neural dynamics within three interconnected brain areas, the orbitofrontal cortex (OFC), the perirhinal cortex (PRH), and the basolateral amygdala (BLA) during each stage of learning and integration in retrospective and prospective memory propagation. To do so, neural activity will be recorded using high-density electrophysiology during behaviour. This approach will be complemented with chemogenetic and optogenetic interrogation methods to delineate the neural circuit involved in memory propagation. Specifically, six reciprocal pathways between the OFC, PRH and BLA will be examined during retrospective and prospective fear propagation. These studies will provide important insight into the dynamic nature of memory, shedding light on how emotional memories become integrated into an existing neural network as well as how acquired emotional memories influence the integration and representation of new memories. The ultimate goal is to lay the basic science platform needed for the development of generalizable and translational knowledge of how adaptive and maladaptive memories spread.