Genetic Differences in Learning and Memory During Stress
Genetic variants that increase expression of a cortisol-binding receptor facilitate changes in learning and memory under stress, suggests two independent human experiments published in eNeuro. These genetic differences could inform personalized treatments of stress-related disorders.
During stressful events, engagement of the brain's memory processes shifts from a complex system involving the hippocampus or prefrontal cortex to a simpler one served by the dorsal striatum. Previous research has implicated the mineralocorticoid receptor (MR) in this shift, which may be beneficial for handling a stressful situation in the short-term but contribute to conditions such as post-traumatic stress disorder and addiction over longer periods.
Lars Schwabe and colleagues explored whether differences in the MR gene underlie these changes using electroencephalography and functional magnetic resonance imaging while participants performed a probability task that can be solved with strategies that engage either the complex or simple memory system. They observed a shift from the hippocampal-dependent to dorsal striatum-dependent memory in the stress condition (induced by public speaking and a difficult math task) only in adults carrying MR genetic variants associated with increased functionality of the receptor. This finding is likely due to reduced processing and connectivity between the amygdala and hippocampus during stress, the authors note.
Corresponding author: Lars Schwabe (University of Hamburg, Germany), Lars.Schwabe@uni-hamburg.de
