Neural activity in our brain can show whether we are experiencing loneliness, scientists say.
US researchers claim sociable people show similar ‘stamps’ of brain activity when they think about themselves and their friends.
In comparison, brain activity in lonely people is more skewed, leading to more dissimilar activity patterns when they think about themselves and others.
While social connection with others is critical to our mental and physical well-being, how the brain maps our relationships with other people has long been a mystery.
Researchers therefore used ‘functional magnetic resonance imaging’ (fMRI) scans to record brain activity while people thought about themselves and others.
The activity patterns of brain regions reflect ‘self-other closeness’ – the closer the relationship, the more the patterns resemble each other. Side bar represents brain activity, measured as changes associated with blood flow
fMRI scans measure brain activity by detecting changes associated with blood flow.
In particular, researchers looked at the medial prefrontal cortex (MPFC) – a brain region that has been associated with self-representation, or how we see ourselves.
The findings revealed new insights into how our brain maps out our social connections and perceptions of friends.
‘If we had a stamp of neural activity that reflected your self-representation and one that reflected that of people whom you are close to, for most of us, our stamps of neural activity would look pretty similar,’ said senior author Meghan L. Meyer, assistant professor at the Dartmouth Social Neuroscience Lab in Hanover, New Hampshire.
‘Yet, for lonelier people, the neural activity was really differentiated from that of other people.’
A functional magnetic resonance imaging (fMRI) device, which measure brain activity by detecting changes associated with blood flow
The study was comprised of 50 college students and community members ranging from the ages of 18 to 47.
The psychologists used MRI scans to examine participants’ brain activity while they thought about themselves, close friends, acquaintances and celebrities at different times.
For each category, they were asked to rate how much a trait described a person on a scale from one to four, from not at all to very much.
The brain seemed to cluster people into three different categories – oneself, one’s own social network and well-known people, like celebrities.
When sociable people thought about their close ones, their brain activity resembled activity patterns from when they had thought about themselves, which scientists labelled the ‘self-other’ overlap.
As levels of loneliness increased, similarities (as measured in brain activity) between friends and acquaintances decreased. Lonely people saw less difference between themselves and a close friend than with a celebrity, compared to the sociable person
A sociable person’s brain also perceived a greater similarity between themselves and a close friend than with a celebrity.
Lonelier people showed less neural similarity between themselves and others in the MPFC, and the demarcations between the three cliques was blurrier in their neural activity.
In other words, the lonelier people are, the less similar their brain looks when they think about themselves and others.
The ‘lonely’ brain was also less able to differentiate between people across the different social categories – for example, it saw less difference between themselves and a close friend than with a celebrity, compared to the sociable person.
‘It’s almost as if you have a specific constellation of neural activity that is activated when you think about yourself, and when you think about your friends, much of the same constellation is recruited,’ said Professor Meyer.
‘If you are lonely though, you activate a fairly different constellation when you think about others than when you think about yourself.
Researchers used brain imaging analyses to assess whether and how the brain organises representations of others based on how connected they are to our own identity
‘It’s as though your brain’s representation of yourself is more disconnected from other people, which is consistent with how lonely people say they feel.’
The research team concluded that the quality of our social life may depend, in part, on the interpersonal maps we carry in our brains.
‘Our results suggest that the social brain may help us navigate our social connections by mapping people based on whether or not they are in our social network, with our closest social ties represented most closely to ourselves,’ said study author Dr Andrea Courtney, a psychologist at Stanford University in California.
‘Loneliness is associated with distortions in this mapping, particularly skewed neural similarity between the self and others and blurred representations of weak ties.’
The study, published in the Journal of Neuroscience, emphasised the importance of acquaintances in promoting access to information, social support and well-being.
How fMRI scans track what happens in the human brain
Functional magnetic resonance imaging (fMRI) is one of the most recently developed forms of neuroimaging.
It measures the metabolic changes that occur within the brain, such as changes in blood flow.
Medical professionals may use fMRI to detect abnormalities within the brain that cannot be found with other imaging techniques, measure the effects of stroke or disease, or guide brain treatment.
It can also be used to examine the brain’s anatomy and determine which parts of the brain are handling critical functions.
A magnetic resonance imaging (MRI) scan uses a magnetic field rather than X-rays to take pictures of body.
The MRI scanner is a hollow machine with a tube running horizontally through its middle.
You lie on a bed that slides into the tube of the scanner.
Equipment used in fMRI scans uses the same technology, but is more compact and lightweight.
The main difference between a normal MRI scan and a fMRI scan is the results that can be obtained.
Whereas a normal MRI scan gives pictures of the structure of the brain, a functional MRI scan shows which parts of the brain are activated when certain tasks are carried out.
This includes language, memory and movement.