Aging brains allow negative memories to fade

It turns out there's ascientific reason why older people tend to see the past throughrose-coloured glasses. A University of Alberta medical researcher, incollaboration with colleagues at Duke University, identified brainactivity that causes older adults to remember fewer negative eventsthan their younger counterparts.

"Seniors actually use their brain differently than younger peoplewhen it comes to storing memory, especially if that memory is anegative one," said study author Dr. Florin Dolcos, an assistantprofessor of psychiatry and neuroscience in the Faculty of Medicine& Dentistry.

The study, published online in December in the U.S.-based journal Psychological Science,found age-related changes in brain activity when participants with anaverage age of 70 where shown standardized images that depicted eitherneutral or strongly negative events.

The research team asked older and younger participants to rate theemotional content of these pictures along a pleasantness scale, whiletheir brain activity was monitored with a functional magnetic resonanceimaging (fMRI) machine, a high-tech device that uses a large magnet totake pictures inside the brain. Thirty minutes later, participants wereunexpectedly asked to recall these images. The older participantsremembered fewer negative images than the younger participants.

Brain scans showed that although both groups had similar activitylevels in the emotional centres of the brain, they differed when itcame to how these centres interacted with the rest of the brain.

The older participants had reduced interactions between theamygdala, a brain region that detects emotions, and the hippocampus, abrain region involved in learning and memory, when shown negativeimages. Scans also showed that older participants had increasedinteractions between the amygdala and the dorsolateral frontal cortex,a brain region involved in higher thinking processes, like controllingemotions. The older participants were using thinking rather thanfeeling processes to store these emotional memories.

Dr. Dolcos conducted the study in collaboration with seniorresearcher Dr. Roberto Cabeza and graduate student Ms. Peggy St.Jacques, both of Duke University.

In another article published earlier this year in the journalNeurobiology of Aging, the team reported that healthy seniors are ableto regulate emotion better than younger people, so they are lessaffected by upsetting events. They also conducted further research tolook at the relationship between emotion, memory and aging.

"Seniors' brains actually work differently than younger individuals– they have somehow trained their brain so that they're less affectedboth during and after an upsetting event," said Dolcos, a member of theAlberta Cognitive Neuroscience Group, a University of Alberta researchteam that explores how the brain works in human thought, includingissues like perception, memory and emotion.

This research may improve understanding of mental health issues likedepression and anxiety, where patients have trouble coping withemotionally challenging situations, and suffer from intrusiverecollection of upsetting memories. These findings may also help toenhance memory in older adults with memory deficits, and assist withresearch related to dementia, including Alzheimer's disease, in whichpatients have difficulty with remembering personal events.

Source: University of Alberta Faculty of Medicine & Dentistry