As babies, we are all born with vastly more neural connections than we need, and these connections get ‘pruned’ as we go through life, cutting out the unused ones, strengthening most the ones we use daily.
As social animals, we learn best and develop neural connections by interacting with others. So what happens when our brains are isolated – when we don’t see or interact with other people for… months?
One BBC Horizon experiment subjected volunteers to 48 hours isolation in complete darkness: devoid of external sensory stimulti, they started to hallucinate. In the equivalent on Channel 5 (In Solitary: The Anti-Social Experiment), participants took in three items to distract themselves and fuel their resolve. Some people took in personal items that carried meaning – but quickly found these intensified feelings of desperation and homesickness; others took in activities to keep them physically or mentally stimulated, and it was these that were found to be most effective. Scientists think this is an essential coping mechanism for staying mentally healthy in isolation. In the longest isolation experiment, undertaken by Stefania Follini, who spent 130 days underground, the interior designer occupied herself with martial arts and decorating her cave.
Isolation also affects us biologically, upsetting cognitive, hormonal, and metabolic activity. Unable to differentiate day and night, Stefania’s diurnal cycle lengthened to 30-35 hours, she lost weight, and her menstrual cycle ceased. Psychologists now think that less than three days in isolation might be enough to cause brain damage – negative changes in the neural networks in our brain.
It’s also been seen in animals. When social animals like rats are isolated, profound behavioural changes result. Different neurochemicals are released in the brain, and neural circuit functions change. The brain becomes hypersensitive, and vulnerable to mental health conditions like depression. Working at this high intensity is exhausting, and its no suprise that those subjected to isolation suffer more everyday illnesses and even die younger.
Lockdown may not be as bad as these isolation experiments, but repeated environmental stresses will ‘prune’ our neural connections and impact health. However, the good news is that the brain is very plastic: it can form new connections, change and recover. Keeping mentally stimulated, whether it’s watching Netflix or starting a decorating project, is the best thing you could do for yourself right now.
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 Pollard, J. C., R. P. Littlejohn, and J. M. Suttie. “Effects of isolation and mixing of social groups on heart rate and behaviour of red deer stags.” Applied Animal Behaviour Science 38.3-4 (1993): 311-322.
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 Bond Energies. Organic Chemistry, Michigan State University.