Recalling positive memories reverses stress-induced depression, suggests a new study. RIKEN-MIT Center for Neural Circuit Genetics scientists have established that artificial reactivation of memories stored during a positive experience can suppress the effects of stress-induced depression.
The research shows how positive and negative memories interact in mood disorders and provides a specific brain circuit for future clinical interventions. The study tackles the long-standing question of whether a positive memory can overwrite a negative one.
To answer the question, the research team used genetic engineering to create mice in which memory cells from a brain area called the dentate gyrus (DG) could be tagged while memories formed, and later reactivated with a blue light-emitting optical fiber implanted in the DG. The team could then turn on memory cells created during previous experiences.
The findings have important implications for the persistence of memory in coping with stress and depression. The interaction of positive and negative experiences and their corresponding memories is poorly understood, but the findings open a path to new approaches in mood disorder therapy that might be helpful for patients in the future.
The authors say it is too early to conclude whether positive memories in general can mitigate the effects of stressful depression.
However, it is clear that DG cells are promising targets for therapeutic approaches to maladaptive mood states. The study is published in Nature