Middle-age-plus memory decline may just be a matter of changing focus

MRI study reveals different parts of the brain involved with younger vs. older subjects
July 15, 2016

When middle-aged and older adults were shown a series of faces, red regions of the brain were more active; these include an area in the medial prefrontal cortex that is associated with self-referential thinking. In young adults, by contrast, blue regions — which include areas important for memory and attention –+ were more active during this task. (credit: N. Rajah, McGill University)

Are you middle-aged or older and having problems remembering details, like where you left the keys or parked your car?

Cheer up, it may simply be the result of a change in what information your brain focuses on during memory formation and retrieval, rather than a decline in brain function, according to a study by McGill University researchers.

In the study, published in the journal, NeuroImage, 112 healthy adults ranging in age from 19 to 76 years were shown a series of faces. Participants were then asked to recall where a particular face appeared on the screen (left or right) and when it appeared (least or most recently). The researchers used functional MRI to analyze which parts of brain were activated during recall of these details.

Different parts of the brain involved

Senior author Natasha Rajah, Director of the Brain Imaging Centre, and colleagues found that young adults activated their visual cortex while successfully performing this task.

But for middle-aged and older adults, their medial prefrontal cortex was activated instead. That’s a part of the brain known to be involved with information having to do with one’s own life and introspection. This may reflect changes in what adults deem “important information” as they age, she said.

Rajah says middle-aged and older adults can improve their recall abilities by learning to focus on external rather than internal information, using mindfulness meditation, for example.*

Rajah is currently analyzing data from a similar study to discern if there are any gender differences in middle-aged brain function as it relates to memory. “At mid-life women are going through a lot of hormonal change. So we’re wondering how much of these results is driven by post-menopausal women.”

The research was supported by the Canadian Institutes of Health Research and by a grant from the Alzheimer’s Society of Canada.

* Other options to improve memory include:

  • Peppermint tea or rosemary essential oil, scientists at Northumbria University found in studies with subjects over age 65, presented at the British Psychological Society’s Annual Conference in Nottingham in April. Rosemary aroma significantly enhanced prospective memory (for things you plan to do).
  • Eight nutrients to protect the aging brain: cocoa flavanols, omega-3 fatty acids, phosphatidylserine and phosphatidic Acid, walnuts, citicoline, choline (found especially in eggs) and magnesium (avocado, soy beans, bananas and dark chocolate), and blueberries, according to a study published in the journal Food Technology. Details here.

Abstract of Changes in the modulation of brain activity during context encoding vs. context retrieval across the adult lifespan

Age-related deficits in context memory may arise from neural changes underlying both encoding and retrieval of context information. Although age-related functional changes in the brain regions supporting context memory begin at midlife, little is known about the functional changes with age that support context memory encoding and retrieval across the adult lifespan. We investigated how age-related functional changes support context memory across the adult lifespan by assessing linear changes with age during successful context encoding and retrieval. Using functional magnetic resonance imaging (fMRI), we compared young, middle-aged and older adults during both encoding and retrieval of spatial and temporal details of faces. Multivariate behavioral partial least squares (B-PLS) analysis of fMRI data identified a pattern of whole brain activity that correlated with a linear age term, and a pattern of whole brain activity that was associated with an age-by-memory phase (encoding vs. retrieval) interaction. Further investigation of this latter effect identified three main findings: 1) reduced phase-related modulation in bilateral fusiform gyrus, left superior/anterior frontal gyrus and right inferior frontal gyrus that started at midlife and continued to older age, 2) reduced phase-related modulation in bilateral inferior parietal lobule that occurred only in older age, and 3) changes in phase-related modulation in older but not younger adults in left middle frontal gyrus and bilateral parahippocampal gyrus that was indicative of age-related over-recruitment. We conclude that age-related reductions in context memory arise in midlife and are related to changes in perceptual recollection and changes in fronto-parietal retrieval monitoring.