Nature sub-issue: Non-drug prevention of pathological aging

Negative emotions, anxiety, and depression are thought to contribute to the development
of neurodegenerative diseases and dementia.
But what are their effects on the brain? Can their harmful effects be limited?

Neuroscientists at the University of Geneva (UNIGE) have observed the activation of the brains in young and old people when faced with the psychological suffering of others
.
The neuronal connections of the elderly show pronounced emotional inertia: negative emotions excessively alter them over a long period of time, especially in the posterior cingulate cortex and amygdala, two brain regions strongly involved in the management of
emotions and autobiographical memories.
The results, which will be published in the journal Nature Aging, show that better management of these emotions — through meditation, for example — can help limit neurodegenerative diseases
.

For the past 20 years, neuroscientists have been studying the brain's response to
emotions.
"We set out to understand what happens at the moment of perceiving an emotional stimulus," explains researcher Dr.
Olga Klimecki, corresponding author of the study, which is part of
a European research project co-directed by UNIGE.
What happens after that, however, remains a mystery
.
How does the brain switch from one emotion to another? How does it return to its initial state? Do mood changes change with age? What is the effect of poor emotional management on the brain?"

Previous psychological research has shown that the ability to change mood quickly is beneficial
for mental health.
Conversely, those who were unable to regulate their emotions and maintained the same emotional state for long periods of time had a higher
risk of depression.
"Our aim was to determine what traces the brain leaves after viewing an emotional scene to assess the brain's response and, most importantly, its recovery mechanism
.
" We focused on older adults to identify possible differences between normal and pathological aging," says Patrik Vuilleumier, professor at the Department of Basic Neurosciences at the Swiss University School of Medicine, a professor at the Swiss University's Centre for Emotional Sciences, who co-directed the work
.

Not all brains are created equal

To observe the volunteers' brain activity using functional MRI, the scientists showed the volunteers short television clips showing people in states of emotional distress — such as in natural disasters or distress — as well as videos
with neutral emotional content.
First, the team compared
27 people over the age of 65 to 29 people around the age of 25.
The same experiment
was then repeated in 127 older adults.

"Older adults typically exhibit different patterns of brain activity and connectivity than younger people," said
Sebastian Baez Lugo, a researcher in Patrik villeumier's lab and lead author of the study.
"This is particularly evident at the level of activation of the default mode network, a brain network
that is highly activated at rest.
Its activity is often interrupted by depression or anxiety, which indicates that it is involved in the regulation
of emotions.
In older adults, part of this network, the posterior cingulate cortex, which processes autobiographical memories, has an increased connection to the amygdala, which processes important emotional stimuli
.
This association was stronger
in those with high levels of anxiety, love to ruminate, or had negative thoughts.
”

Empathy and aging

However, older people tend to regulate their emotions better than younger people and are more likely to focus on positive details, even during
negative events.
But changes in the connection between the posterior cingulate cortex and the amygdala may indicate deviations from normal aging phenomena, which are particularly prominent
in those who exhibit more anxiety, reflection, and negative emotions.
The posterior cingulate cortex is one of the areas most affected by dementia, suggesting that the presence of these symptoms may increase the risk of
neurodegenerative diseases.

"Does poor emotion regulation and anxiety increase the risk of dementia, or is it the opposite?" We still don't know," Sebastian Baez Lugo said
.
"Our hypothesis is that more anxious people have no or less capacity
for emotional distance.
In the context of aging, the mechanism of emotional inertia can be explained by the fact that the brains of these people are constantly 'frozen' in
a negative state by associating the suffering of others with their own emotional memories.
”

Is meditation a workaround?

Is it possible to prevent dementia through the mechanism of emotional inertia? The research team is currently conducting an 18-month interventional study to evaluate the effects of
foreign language learning and meditation practice.
The authors add: "To further refine our results, we will also compare the effects of two types of meditation: mindfulness, which is fixing oneself in the present moment and focusing on one's own feelings, and so-called 'compassion' meditation, which aims to positively increase positive emotions
towards others.
"

The study is part of a larger European study that aimed to assess the effects of
non-pharmacological interventions on better aging.

Exposure to negative socio-emotional events induces sustained alteration of resting-state brain networks in older adults.
Nature Aging, 2023