Negative emotions, depression, and anxiety are believed to play a major role in the development of neurodegenerative conditions such as dementia. A team of researchers led by the University of Geneva (UNIGE) set out to better understand the process of aging by investigating the activation of the brains of both young and older adults when confronted with the psychological distress of others
The experts found that the neuronal connections of the elderly show significant emotional inertia, with negative emotions modifying them excessively over an extended period of time, especially in the posterior cingulate cortex and the amygdala (two brain regions involved in the regulation of emotions and autobiographical memory). The findings suggest that a better management of negative emotions – through meditation, for instance – could help limit neurodegeneration.
“We are beginning to understand what happens at the moment of perception of an emotional stimulus,” said study senior author Olga Klimecki, an expert in Affective Sciences at UNIGE. “However, what happens afterwards remains a mystery. How does the brain switch from one emotion to another? How does it return to its initial state? Does emotional variability change with age? What are the consequences for the brain of mismanagement of emotions?”
Previous studies have found than a capacity to change emotions quickly is beneficial for mental health, and that people who remain in the same emotional state for a long period of time have an increased risk of depression.
“Our aim was to determine what cerebral trace remains after the viewing of emotional scenes, in order to evaluate the brain’s reaction, and, above all, its recovery mechanisms. We focused on the older adults, in order to identify possible differences between normal and pathological aging,” said study co-author Patrik Vuilleumie, a professor of Basic Neurosciences at the same university.
The researchers showed both young and older participants short television clips with people experiencing emotional distress, as well as videos with a neutral content, and observed their brain activity using functional MRI. “Older people generally show a different pattern of brain activity and connectivity from younger people,” said study co-author Sebastian Baez Lugo, a cognitive neuroscientist at UNIGE.
“This is particularly noticeable in the level of activation of the default mode network, a brain network that is highly activated in resting state. Its activity is frequently disrupted by depression or anxiety, suggesting that it is involved in the regulation of emotions. In the older adults, part of this network, the posterior cingulate cortex, which processes autobiographical memory, shows an increase in its connections with the amygdala, which processes important emotional stimuli. These connections are stronger in subjects with high anxiety scores, with rumination, or with negative thoughts.”
However, most older people tend to regulate their emotions better than younger ones, and focus more easily on positive details. Thus, the changes in connectivity between the posterior cingulate cortex and the amygdala could indicate a deviation from normal aging, which is accentuated in people with more negative emotions, anxiety, and rumination.
“Is it poor emotional regulation and anxiety that increases the risk of dementia or the other way around? We still don’t know,” said Baez Lugo. “Our hypothesis is that more anxious people would have no or less capacity for emotional distancing. The mechanism of emotional inertia in the context of aging would then be explained by the fact that the brain of these people remains ‘frozen’ in a negative state by relating the suffering of others to their own emotional memories.”
In future research, the scientists aim to investigate whether activities such as meditation or foreign language learning may help prevent dementia by acting on the mechanisms of emotional inertia.
The study is published in the journal Nature Aging.
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