By Raluca Blujdea
What happens when our evolutionary predisposition to be social actually makes us sick? This is the predicament we find ourselves in today, at a scale never seen before. Social distancing has been vital, but the current situation is inherently stressful and will affect our minds and bodies. But how?
In 328 BC, Aristotle stated that ‘man is by nature a social animal’. This has yet to be disproven; we need others to survive and prosper and we form entire cultures and religions around this. Our social behavior has evolved this way because, in a group, you are generally more protected. But our close proximity has put us at a higher risk for pathogen infection, such as what is happening now: the invasion of the notorious SARS-CoV-2, which causes COVID-19 (Coronavirus Disease-2019).
The virus is highly contagious and deadly, so for the past months, most of us have been in government-imposed lockdowns. People isolated and distanced themselves from others in an attempt to control the spread and ‘flatten the curve’ – building barriers within our society. There is currently no cure, but clinical trials are well underway and correct hand-washing together with wearing face-masks means that we can regain part of our mobility. As the curve flattens, and with correct guidelines, lockdowns are starting to ease.
Still, the past few months witnessed isolation on a scale that has never happened before. This has put an enormous strain on our mental health: all over the world, people (including me) are experiencing mood changes and anxiety. Why is this happening and how is isolation affecting our brain? The answer is complicated.
The Nature of the Social Animals
Humans are highly social beings, but we are not alone in this. Microbes, bees, fish, gorillas, rats, mice, etc., all are predisposed to social behaviors1. It is essential for survival. Feelings of isolation or separation from others do not only cause us emotional unhappiness, they can target our health and livelihood.
From birth to adulthood, we are dependent on our society and family. Our brain reflects this and contains areas highly specialized in social behaviors, the so-called “social brain” (figure 1). You have areas for protection like the amygdala, the prefrontal cortex, the anterior cingulate cortex, and the insula. These are involved in social threat surveillance and aversion, but also for social motivation. They make decisions on how you behave when social dangers arise.
How do you recognize a social danger? The brain pays attention to how others are acting in a social context. The way you perceive someone’s behavior and facial expressions are controlled by the fusiform face area, the extrastriate body area in the visual cortex and the mirroring system. Together, they control how you respond. In other words, our brain assesses how others behave socially and adapts to our highly fluid social environment2.
A change in the way we interact with others, such as in isolation, will affect these networks. Isolation has been studied extensively in human and non-human subjects, mainly focusing on perceived social isolation (the actual fact of realizing you are alone) and the loneliness associated with it4,6,8.
Loneliness, whether related to lockdown isolation, a journey to space, solitary confinement, or even being in a nursing home, can actually be painful. When you perceive separation, your brain responds in a similar pattern as it would to physical pain through the anterior insula and the anterior cingulate cortex5,6 (part of the cognitive control and motivation system). For example, if you burn your hand, you will seek help; similarly, loneliness pain will drive you to seek social interaction for that ‘increased survival in groups’ effect.
Survival 101: Stress and Danger
When we are faced with danger, your body will trigger the “fight or flight” response in a very small, almond-shaped brain region called the amygdala. This prepares you to protect yourself against a physical threat or escape to safety. But it also encourages us to stay within a group. This was not feasible in the last few months, adding to the stressful situation. The body recognizes modern-day stress, such as chronic isolation, as a danger7 and pandemic-isolation-induced loneliness therefore might be posing chronic stress on you.
In the short-term, stress is meant to allow your body to focus resources wisely to survive, but in the long-term, the survival-mode can be detrimental to your overall health. Chronic stress can increase cardiac output (blood pressure) while decreasing inflammatory control, healthy sleeping, immunity, and expression of genes regulating stress8.
In other words, your response to stress makes you more vigilant by preparing your muscles and heart for action and decreases your sleep quality. But it also decreases your immune response. So, it might make you more prone to infection, unfavorable during a pandemic to say the least…. This might sound counterintuitive, but it does this to make you more likely to escape a dangerous situation – it is prioritizing. If your body uses the energy to help you run or fight, you can deal with the rest later.
Danger can be physical, but it can be emotional too. Your brain responds to low quality social interactions and loneliness similar to physical danger8,10. If you are lonely or scared, your body will be more alert to any negative stimuli, therefore heightening your responses. Long-term ‘looking over your shoulder’ can lead to increased heart disease, less healthy lifestyles, and even lethality7,8.
Your brain on loneliness
You respond to social isolation stress as you would to any other stressor. The stress response is a highly complex mechanism that starts in the frontal and limbic parts (emotion control center) of the brain, part of which is the amygdala. So, your emotional regulation and memory are affected, making you more prone to anger and fear when stressed.
The amygdala under duress actually grows in size13. It pushes on its anxiety-related9 neighbor, the BNST (the bed nucleus of the stria terminalis; the yellow blob in the figures). The BNST then activates the hypothalamus and the pituitary response which signal to the adrenal cortex. The adrenal cortex releases the stress hormone ‘cortisol’. This travels through the body, tapping into your glucose stores to increase energy levels and blood pressure (among others, figure 2) as part of the survival mechanism10. Chronic exposure of this on the heart can lead to heart problems.
The pituitary also releases a hormone known as oxytocin11. You may recognize this chemical as the ‘love hormone’ and it is involved in social behaviors like hugging, maternal behaviors, and sex. But it is also released during stress, as a coping mechanism12 and it drives that survival need to connect with others. Oxytocin travels through the blood system but it also affects the brain regions, like the insula for emotional control and the BNST for decrease of anxiety.
To top this all off, structural changes can also occur. The prefrontal cortex may shrink and disconnect from the rest13. This is your focus, emotional regulation, and decision-making center, therefore a change in it can cause you to lose focus more easily. The social brain areas may become less activated which can affect your trust in others, making re-connecting harder.
There is a biological reason for your struggle, but you can take control
As I watch the Space-X launch, I can’t help but wonder if this pandemic might have prepared the astronauts for the isolation in space and whether they are better off flying away from Covid-19. Still, our lockdown isolation differs from theirs or the studies on animals; there they are completely excluded from the rest of society, which adds greatly to the emotional pain of loneliness. But during the lockdowns or social distancing, we are not excluded. Almost the whole world experiences the same thing, so the long-term effects remain to be seen. We can’t generalize a response and we have to remember that the brain is a fickle organ.
So, what can you do to help it? Take advantage of the internet (imagine what it was like during the Spanish flu) and stay connected, but keep in mind that texts may not be enough. Your brain requires a more emotional connection. The Dutch government has even issued advice on finding a sex-buddy, as sex and hugs increase oxytocin.
But emotional connection can also come from music. We have all seen the balcony concerts all over the world, bringing people together. But music doesn’t only do that. Music actually shows a similar response to physical touch and releases oxytocin14. It has been shown that singing, jamming, and listening to music increase your levels of the love hormone, hinting that songs can literally maintain our health and sanity during these trying times.
Flattening the curve has not been easy, but it has helped to protect those at risk. Now, countries are slowly coming up for air and so can we – find a (sex/hug) buddy, listen to music, jam with some friends, exercise (mental and physical), and meet up with a few close friends to have that long-awaited beer by the Amstel. So, yes your frontal cortex, pituitary, and amygdala cause you to feel the way you feel, but you are the one who can take control.
About the writer
Raluca is a second year VU Master of Neurosciences student who is particularly interested in neurological development, neurodegenerative disorders and science communication.
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