Psychobiology of Conditioned Memory Modulation
Researcher:
Department or Unit:
Psychology
Sponsor:
NSERC Discovery Grant
Project Dates:
to
About the Project
In classical conditioning, the conditioned stimulus (“CS” – an environment, sound, smell) is a relatively
neutral stimulus that, after association with a biologically significant stimulus (the unconditioned stimulus;
“US” – food, shock, various drugs), comes to trigger learned or “conditioned” responses. Conditioned
responses are typically quite complex as they encompass motor, emotional, and physiological reactions.
The projecct explores “conditioned memory modulation,” focussing on how CSs modulate the strength
of newly acquired memories.
My laboratory has been the first to conduct a systematic empirical comparison of memory modulation by
CSs paired with incentive and aversive USs. Because the modulatory effects of CSs appeared
indistinguishable from those of their associated USs, and were observed in their absence, we suggested
that learned CSs can gain the ability to independently modulate activity of memory systems in the brain.
The overarching objective of the research is to identify key psychological and neurobiological
mechanisms by which CSs modulate memory consolidation; a timedependent neurobiological process
of stabilization of newly formed memory traces.
The scientific approach will involve conditioning procedures in both male and female SpragueDawley
laboratory rats, modulation of memory consolidation by posttraining exposure to CSs/USs, memory testing
(object identity/location recognition), pharmacology, as well as manipulations of neural
activity by compounds infused directly in discrete brain regions.
In the next five years, the aims are to explore the roles of cholinergic, noradrenergic, and dopaminergic
mechanisms/pathways, as well as of the extended amygdala and its projections, in modulation of memory
consolidation by CSs and their USs. We have also designed studies to elucidate how different psychological
functions of CSs impact memory consolidation. This research will provide training opportunities for at least
6 PhD, 5 MSc, and 17 Undergraduate Thesis students.
The research program represents a novel integrative psychological and neurobiological
investigation of memory modulation by conditioned stimuli. Conditioning processes play many roles in
human and animal behavior, and the possibility that CSs impact the stability of newly formed memories
suggests a ubiquitous involvement in normal learning functions. Moreover, conditioning factors play
important roles in psychopathologies such as substance dependence and posttraumatic
stress disorders. Therefore, a detailed understanding of how CSs impact memory can eventually spur alternative
psychological and pharmacological approaches to improve the lives of many Canadians affected by these
debilitating conditions.