Exposure to negative emotions alters brain activity
A team of neuroscientists has considered what consequences a poor management of emotions has for the brain. To do this, a team from the University of Geneva (UNIGE) observed the activation of the brain of young and old adults before the psychological suffering of others. Negative emotions, anxiety and depression favor the appearance of neurodegenerative diseases and dementia. But until now, its impact on the brain and whether it is possible to limit its harmful effects have not been known.
The neural connections of the elderly show an important emotional inertia: negative emotions they modify them excessively and for a long time, especially in the posterior cingulate cortex and the amygdala, two brain regions highly involved in managing emotions and autobiographical memory. These results, which are published in Nature Agingindicate that better management of these emotions —through meditation, for example— could help limit neurodegeneration.
«For 20 years, neuroscientists have studied how the brain reacts to emotions. We are beginning to understand what happens at the moment of perception of an emotional stimulus”, explains Olga Klimecki, a researcher at the UNIGE Swiss Center for Affective Sciences, co-author of the paper.
Ability to regulate emotions
What happens after perceiving a negative emotion in the brain and whether the process changes with age was a mystery. Previous studies in psychology have shown that the ability to quickly switch between emotions is beneficial for mental health. On the contrary, people unable to regulate them and who remain in the same state for a long time are at greater risk of suffering from depression.
«Our objective was to determine what brain trace remains after viewing emotional scenes, to assess the brain’s reaction and, above all, its recovery mechanisms. We focus on the elderly, to identify possible differences between normal and pathological aging», says Patrik Vuilleumier, a professor in the Department of Basic Neurosciences at the Faculty of Medicine and the UNIGE Swiss Center for Affective Sciences, who co-directed this work.
differences between brains
The scientists showed the volunteers short television clips showing people in a state of emotional distress—during a natural disaster or distress situation, for example—as well as emotionally neutral videos, in order to observe their activity. brain by functional magnetic resonance imaging. First, the team compared a group of 27 people over the age of 65 with another group of 29 people in their 25s. The experiment was then repeated with 127 older adults.
“The latter usually show a pattern of brain activity and connectivity different from the youth», says Sebastián Báez Lugo, a researcher in Patrik Vuilleumier’s laboratory and first author of this work.
“In older adults, part of the brain network, the posterior cingulate cortex, which processes autobiographical memory, shows a increase your 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,” adds the lead author of the study.
Older people tend to regulate their emotions better than younger people and focus more easily on positive details, even during a negative event. However, changes in the connectivity between the posterior cingulate cortex and the amygdala indicate a deviation from the normal phenomenon of aging, accentuated in people who show more anxiety, rumination and negative emotions, according to the researchers. This cortex is one of the regions most affected by dementia, suggesting that the presence of these symptoms could increase the risk of neurodegenerative disease.
“Is it poor emotional regulation and anxiety that increase the risk of dementia or the other way around? We still don’t know,” says Báez Lugo. “Our hypothesis is that the most anxious people would have null or less capacity for emotional distancing. The mechanism of emotional inertia in the context of aging would be explained by the fact that the brain of these people remains ‘frozen’ in a negative state, as they relate the suffering of others to their own emotional memories”, he continues.
Meditation and language teaching
To find out if this inertia can be acted upon, the research team is now carrying out a study that will last 18 months to evaluate the effects of learning foreign languages, on the one hand, and the practice of meditation, on the other.
«To further refine our results, we will also compare the effects of two types of meditation: mindfulness, which consists of anchoring yourself in the present to concentrate on your own feelings, and what is known as ‘compassionate’ meditationwhose goal is to actively increase positive emotions towards others,” the researchers conclude.