It can also change what we remember, particularly when an experience is emotionally intense or personally meaningful. Scientists have long known that cortisol, a hormone released during stressful situations, can strengthen emotional memories. What has been less clear is exactly how this happens inside the brain.
Researchers at Yale University have now uncovered important clues. Their study reveals that cortisol strengthens emotional memories by changing how brain networks involved in emotion and memory function and communicate with one another. The findings offer a deeper understanding of why certain experiences leave such powerful impressions while others quickly fade.
"We all experience stress, and my lab is interested in understanding how stress can be helpful," said corresponding author Elizabeth Goldfarb, an assistant professor of psychiatry at Yale School of Medicine and of psychology in the Faculty of Arts and Sciences. The findings were published in the journal Science Advances. Previous research involving both humans and rodents has shown that stress and cortisol can improve memory for emotional events.
Scientists also know that certain brain regions, including the amygdala, play an essential role in this process. The amygdala is particularly important for processing emotions and identifying experiences that may be significant. However, understanding precisely how cortisol strengthens memories has been challenging.
Many brain regions participate in several mental functions, making it difficult to determine whether the hormone is influencing emotional responses, memory formation, or both. "Forming memories for emotional experiences involves different processes in the brain: first, perceiving an experience as emotional or intense, and second, encoding that experience into long-term memory," said Goldfarb, who is also a member of Yale's Wu Tsai Institute, an interdisciplinary research initiative that explores cognition. The researchers wanted to examine these processes separately to determine how cortisol affects the brain's ability to recognize emotional significance and preserve an experience as a lasting memory.
Watching the Brain Form Emotional Memories To investigate, the Yale team conducted an experiment in which participants took a pill containing either hydrocortisone, a form of cortisol, or an inactive placebo. They then viewed a series of pictures while undergoing functional MRI (fMRI) scanning. This imaging technique measures changes in blood flow and oxygen levels associated with brain activity, allowing researchers to identify which areas of the brain are more active during different tasks.
Extract — continue reading at the source.
