The results converged on the default network as most impacted by perceived isolation and loneliness.
A wealth of data
Well before the pandemic
, loneliness was increasingly being seen as a public health concern
, enough so that the United Kingdom appointed a minister for loneliness
Data has shown that lonely adults are about
1.64 times more likely to develop dementia compared with those who don’t self-report loneliness
一个 2015 review of worldwide studies
Results like those motivated the researchers to comb through brain images from
40,000 科目, all pulled from the UK Biobank
, a large-scale database storing biomedical information from some
500,000 British people
Participants in that study, who ranged in age from 40 至 69, filled out assessments that included questions asking whether they felt lonely or not.
The researchers then compared MRI scans of self-identified lonely people with those who did not feel loneliness on a regular basis.
The sheer size of the data sample is a rarity in this area of science, Spreng said, and it was the result of the biobank dramatically scaling up its available brain images this past February.
“We started working with that immediately when they came out and it was very exciting,” Spreng said.
Prior to this, most of his neuroscience work had focused on cohorts with just hundreds of participants — a significant number in itself. 但现在, with tens of thousands of subjects’ data to draw from, there was a lot more to learn.
研究人员’ hypothesis that the default network in the brain was active during loneliness was a logical one
, because those are parts involved in thinking about self
, according to Dr
. Kenneth Heilman
, professor emeritus in the University of Florida’s department of neurology
, whose books include
“Creativity and the Brain
” 和 “The Believer’s Brain
.” Heilman was not involved in the McGill study
“There’s an old, old saying in neurology that we always use. And that’s ‘use it or lose it,'” Heilman said.
Although parts of the brain primed for creativity and thinking about the self can grow during loneliness, that could mean that other social parts of the brain would atrophy from inactivity.
“The big question comes up, do you start losing other parts of the brain that are important for interactions?” Heilman asked. “If you don’t use them, 最终, will that lead to more of a dementing kind of disorder?”
Insights into Alzheimer’s
One key way this study could benefit medicine more broadly is by helping scientists better understand how social isolation — an even more crucial topic during an isolating pandemic — might change the structure of the brain, putting people at risk for Alzheimer’s as they age.
“There’s still a lot of other factors that need to be examined, like how does loneliness interact with APOE-4 genotype,” Spreng said.
That gene has been linked to up to
25% of Alzheimer’s cases
, 根据 Alzheimer’s Association
And because seniors at risk for dementia are often more isolated when living alone or in shared living facilities, more research could reveal how loneliness could exacerbate an already present genetic predisposition.
“This first study was really important in terms of identifying what parts of the brain are impacted by loneliness,” 他说. “We’re using that information and we’re following a large sample of older adults. We’re seeing how their brain ages over multiple years, and how their experience of loneliness might actually accelerate atrophy patterns.”
And the study has greater significance after a pandemic year in which social isolation is more common.
“Feeling socially connected is extremely important,” Spreng said. “Coming out of Covid-related isolation will probably be a lot easier for some people, young adults in particular. Older adults may require more assistance.”