By Jessie Yaros, Graduate Student in the Translational Neurobiology Laboratory
“Those were the good old days”. Chances are you’ve expressed this statement yourself, or heard a parent or grandparent share the sentiment. Nostalgia is almost second nature for us, and seems like a healthy way to reflect on the past. Who wouldn’t want to reminisce about childhood, college, or that first job, when life was wonderfully uncomplicated. Viewing life through rose-tinted glasses, however, may not be such a good thing. New research from UC Irvine suggests that this selective remembering of positive experiences can be a marker for memory loss in the elderly.
In a study that appears in the August edition of Learning and Memory, Michael Yassa, associate professor of neurobiology & behavior and neurology, and colleagues designed and employed a test that uses participants’ recall of stories with differing emotional content to identify memory deficits and decline. The findings suggest that older adults with minor memory deficits are more likely to learn and retain positive information, relative to negative or neutral information.
Participants who were administered the new test, coined the Emotional Logical Memory Test (ELMT) , listened to various stories, and immediately afterwards were asked to recite all the details they could remember. They reported the events from memory again after 20 minutes, and at a subsequent visit one week later. This allowed the neurobiologists to observe how recall varied with the emotional tone of stories as time passed.
The research was overseen by Stephanie Leal, who recently earned a doctorate at UCI, and Jessica Noche, a clinical research specialist in the Yassa lab.
“We were interested in seeing how emotional memory changes over time, so we developed a test to detect the subtle changes that occur with different types of emotional memory in older adults,” Noche said. “We specifically compared responses to positive, negative and neutral stories to learn whether emotional valence had a role in the way stories were remembered over time.”
Study participants also took a verbal learning exam to gauge general memory performance. This served to distinguish between individuals who were high performers and those who were low performers (i.e., showing subtle memory deficits). Importantly, none of them suffered from overt memory problems severe enough for a clinical diagnosis.
Analyzing the results, researchers found that low-performing older adults exhibited a large “positivity effect,” or propensity to remember positive information. However, this came at the expense of retaining neutral material. On the other hand, high-performing older adults could recall more from neutral stories at the expense of retaining positive details.
Past studies have generated contradictory results on the existence of the positivity effect in aging populations. Yassa’s research suggests that prior inconsistent detection of the emotional preference may be caused by grouping older adults together, irrespective of high and low memory performance.
It is likely that this observed preference for positive information in older adults is connected to changes in the brain associated with aging. “We suggest that this bias toward positive retention in low-performing adults may be a compensatory mechanism that masks the effects of memory loss in the elderly, although this remains speculative,” Yassa said. “It’s possible that selectively remembering positive information may be related to changes in the brain networks supporting memory, emotional valence and reward value. Future studies using brain imaging techniques will be essential in understanding the mechanisms underlying this effect.”
Since all study participants at the time of testing had no memory complaints, researchers believe that the ELMT may tap into subtle changes in emotional memory abilities prior to obvious symptoms of cognitive decline. Further work will be necessary to establish whether participants expressing the positivity effect are more likely to develop Alzheimer’s disease. If so, the test could prove to be a valuable tool in the early detection of Alzheimer’s susceptibility.
Elizabeth Murray, a research specialist in Yassa’s lab at UCI, also contributed to the study, which received support from the National Institutes of Health (grants R01 MH102392, R21 AG049220 and P50 AG 16573). UCI’s Center for the Neurobiology of Learning & Memory and the Institute for Memory Impairments & Neurological Disorders also provided support.
Jessica (Jessie) Yaros received her Bachelors in Science in Cognitive Neuroscience from the University of California, San Diego. After graduating, she joined the Laboratory of Neuro Imaging (LONI) at UCLA, and later USC, to provide support in managing the Image & Data Archive (IDA) database, and dissemination of ADNI Whole Genome Sequence data. Jessie joined the Translational Neurobiology lab in 2015. Her current research explores the neural basis of the Other Race Effect- the tendency to best recognize individuals within one’s own race. She is interested in communicating science to the lay audience and appeared recently on Friends of Joe’s Big Ideas on NPR. Click here to find out more about Jessie.