Why do we have ‘senior moments’?

Why do we have ‘senior moments’?

 As we get older, we often ascribe forgetting where we put the house keys or what the name of a particular item is as just a “senior moment” rather than simply being forgetful.

New research has offered an insight into the difference between these “senior moments” and other forgetful episodes.

Scientists at the University of California used functional resonance imaging (fMRI) to analyse how the brain works when recalling information in a bid to understand what happens during forgetful episodes.

The 40 healthy participants - of which half were between ages 18 and 31 and the other half between ages 64 and 89 - were asked to complete two tasks. 

The first involved identifying commonplace objects and then distinguishing them from new ones, and the fMRI was used to see which areas of the brain were being used by the brain during the task.

“Some of the images were identical to ones they’d seen before, some were brand new, and others were similar to ones they’d seen earlier, we may have changed the colour or the size,” said Michael Yassa, senior author and director of the Centre for the Neurobiology of Learning and Memory at the university.

The study found that older adults struggled with the subtle changes and didn’t perform as well as the younger adults in identifying new similar-looking objects.

For the second task, participants had to rely on their spatial memory to determine whether objects had changed location. 

In this task, the older participants came out on top.

Images worth a thousand words

From the fMRI imaging, the team found that these two tasks rely on different parts of the brain.

During the first task, the anterolateral entorhinal cortex appeared to be a contributing factor in the performance of older participants, whereas the second task relied on a different part of the brain called the posteromedial entorhinal cortex.

The anterolateral entorhinal cortex acts as the messenger between the hippocampus, where memory is encoded, and the neocortex, which is involved in long-term memory storage. Signal loss in this region of the brain has already been associated with people suffering from Alzheimer’s disease, but this research means that the same loss of signal appears in people who have aged normally and that it could be the reason behind “senior moments”.

From the second task, the better performance of the older participants suggest that this area of the brain is less affected by aging than other areas.

Why does it matter?

These findings suggest that “not all memory changes equally with aging”, said lead author Zachariah Reagh.

This means that forgetting where you left your keys may have nothing to do with your age.

“This suggests that the brain-aging process is selective,” said Yassa.

As a result, these findings could help with identifying patients at risk of dementia in the future.

Image: UCI CNLM / Instagram

Our Partners