Get a hold of yourself: Negative thoughts speed up brain aging, neurodegeneration

GENEVA — Some people tend to be more emotionally open than others, but pretty much everyone has to face their feelings at some time or another. Negative emotions, anxiety, or the occasional bout of depression may be unavoidable in life, but fascinating new findings show how managing emotions can help limit neurodegeneration and slow down brain aging.

Neuroscientists at the University of Geneva (UNIGE) observed how the brains of both young and older adults activated when confronted with the psychological suffering of others. Among older study subjects, neuronal connections displayed significant emotional inertia. In other words, negative emotions felt by those older adults appear to have excessively modified their neuronal connections over an extended period of time.

This trend was most pronounced in the posterior cingulate cortex and the amygdala. Both of those brain regions are strongly involved in managing emotions and autobiographical memory.

Study authors explain that these results indicate better management of negative emotions, via meditation for example, may help curb neurodegeneration. This work is just the latest in modern science’s efforts to better understand the brain; researchers have been investigating how the brain reacts to emotions for the past two decades.

‘‘We are beginning to understand what happens at the moment of perception of an emotional stimulus,’’ explains Dr. Olga Klimecki, a researcher at the UNIGE’s Swiss Centre for Affective Sciences and at the Deutsches Zentrum für Neurodegenerative Erkrankungen, last author of this study carried out as part of a European research project co-directed by the UNIGE, in a university release. ‘‘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?’’

‘Older people show a different pattern of brain activity and connectivity’

Earlier studies in psychology have found that the capacity to change one’s emotions in a quick manner can benefit mental health. Meanwhile, those who are unable to regulate their emotions, and thus remain in the same emotional state for longer periods, are usually at a higher 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,’’ explains Patrik Vuilleumier, professor in the Department of Basic Neurosciences at the Faculty of Medicine and at the Swiss Centre for Affective Sciences at the UNIGE, who co-directed this study.

Researchers showed participants a series of short TV clips displaying people in a state of emotional suffering. For example, during a natural disaster. Videos showing neutral emotional content were also presented, and subjects’ brain activity was observed via functional MRI. To start, a cohort of 27 people over 65 years of age were compared with a group of 29 people aged around 25 years old. Then, the same experiment was carried out again with 127 older adults.

‘‘Older people generally show a different pattern of brain activity and connectivity from younger people,’’ comments Sebastian Baez Lugo, a researcher in Patrik Vuilleumier’s laboratory and the first author of this study. ‘‘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.’’

Future study will test how mindfulness meditation can blunt negative emotions

It’s important to note that older people are generally better equipped to regulate their emotions than their younger counterparts. Older adults can usually focus more easily on positive details, even during a negative event. However, changes in connectivity between the posterior cingulate cortex and the amygdala suggest a deviation in the normal aging process, accentuated among those who show more anxiety, rumination, and negative emotions. The posterior cingulate cortex is one of the brain regions most affected by dementia, which indicates that the presence of these symptoms could increase neurodegenerative disease risk.

‘‘Is it poor emotional regulation and anxiety that increases the risk of dementia or the other way around? We still don’t know,’’ adds Sebastian 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.”

So, is it possible to prevent dementia by acting on the emotional inertia mechanism? Study authors are now conducting an 18-month interventional study focusing on the effects of both foreign language learning and meditation.

‘‘In order to further refine our results, we will also compare the effects of two types of meditation: mindfulness, which consists of anchoring oneself in the present in order to concentrate on one’s own feelings, and what  is known as ‘compassionate’ meditation, which aims to actively increase positive emotions towards others,’’ study authors conclude.

The study is published in Nature Aging.

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