ast week, my whole outlook on the world was transformed by a sheet of blank paper. Not just any paper, but beautifully embossed stationery, silky to the touch and decadent to write on. It was a gift from a dear friend and colleague. We collaborate over Zoom every week, so I could have thanked him on video, but instead I wrote a short note of gratitude and love, and posted it to him. His delight on receipt a few days later mirrored my own, and we shared a moment of emotional connection. Before that moment, I was immersed in yet another “Blursday” full of Covid-saturated, this-will-never-end moroseness, staring alone at a screen that makes my skin look pallid. Afterwards, to my surprise, I was alight in a sprawling web of human connections. But I shouldn’t have been surprised: I am a neuroscientist who studies how the brain creates your mood. In fact, if you understand a bit about your brain’s inner workings, it may help you to cultivate comfort from those around you, whether physically or in spirit, in difficult times. Research shows that in every moment of your life, your brain regulates the insides of your body, including your organs, hormones and immune system, to keep you alive. The process is like running a household budget, but instead of money, your brain budgets water, salt, glucose and other bodily resources as you gain and lose them. Actions that spend resources, such as exercise or stressful conversations, are like withdrawals from your account. Actions that replenish resources, such as eating, sleeping, and cuddling a beloved pet are like deposits. You aren’t wired to notice the details of your brain’s ongoing budgeting process. You don’t feel your blood rushing through your veins, your liver pumping bile or your cells metabolising glucose, as precisely as you see objects and hear distinctive sounds. Instead, deep inside your body, this symphony of coordinated changes produces simple feelings: pleasant, unpleasant, active and calm. When something happens in your world that requires a deposit or withdrawal, it disturbs this inner coordination and you may experience a change in mood, from a whisper of comfort to a tsunami of dread. The change doesn’t reveal what happened or what to do about it, only that your brain believes something important is about to occur. You might know it as a “gut feeling” or an “intuition”. Scientists call it “affect”. I think of it as a kind of sixth sense, like Spider-Man’s “spider sense” but without the precision. Your ever-flowing river of feeling, sometimes a dribble, sometimes a torrent, is grounded in your brain’s body-budgeting activities as you are prompted and prodded by the world outside your skull. Before Covid-19, body budgeting in modern life was already treacherous. Many of us were sleep deprived, stressing out on social media, not exercising enough and eating pseudo-foods loaded with budget-warping refined sugar and bad fats. The pandemic exacerbated these problems, along with financial worries, parenting pressures, social isolation and, of course, the fear of dying. Depression rates doubled in the UK and tripled in the US. Overall, our body budgets are seeing more withdrawals and fewer deposits. But in these challenges we face we may discover seeds of resilience, with neuroscience as the flashlight. Many things in the outside world can nudge (or shove) your body budget, and that includes other human beings. In a very real, biological way, we are connected to one another through body budgeting. Friends, family and strangers can do and say things that send your spider sense creeping (or careening) this way or that, and you return the favour. In a moment of trust or affection, for example, heart rates or breathing may synchronise. When you raise your voice, or even your eyebrow, you might affect the chemicals carried in someone else’s bloodstream. These sorts of physical connections happen between infants and their caregivers, between therapists and their clients, among friends or lovers and even among people moving together in a yoga class or singing in a choir. People notice these body-budget tweaks mainly as changes in mood. Being the caretakers of each other’s body budgets is challenging when so many of us feel lonely or are physically alone. But social distancing doesn’t have to mean social isolation. Humans have a special power to connect with and regulate each other in another way, even at a distance: with words. If you’ve ever received a text message from a loved one and felt a rush of warmth, or been criticised by your boss and felt like you’d been punched in the gut, you know what I’m talking about. Words are tools for regulating bodies. In my research lab, we run experiments to demonstrate this power of words. Our participants lie still in a brain scanner and listen to evocative descriptions of different situations. One is about walking into your childhood home and being smothered in hugs and smiles. Another is about awakening to your buzzing alarm clock and finding a sweet note from your significant other. As they listen, we see increased activity in brain regions that control heart rate, breathing, metabolism and the immune system. Yes, the same brain regions that process language also help to run your body budget. Words have power over your biology – your brain wiring guarantees it. Our participants also had increased activity in brain regions involved in vision and movement, even though they were lying still with their eyes closed. Their brains were changing the firing of their own neurons to simulate sight and motion in their mind’s eye. This same ability can build a sense of connection, from a few seconds of poor-quality mobile phone audio, or from a rectangle of pixels in the shape of a friend’s face. Your brain fills in the gaps – the sense data that you don’t receive through these media – and can ease your body budget deficit in the moment. In the midst of social distancing, my Zoom friend and I rediscovered the body-budgeting benefits of older means of communication, such as letter writing. The handwriting of someone we care about can have an unexpected emotional impact. A piece of paper becomes a wave of love, a flood of gratitude, a belly-aching laugh. These days, when I compose letters on my silky stationery, or share a meal with friends in other countries through a laptop on the kitchen table, sometimes I marvel that my world during Covid has actually expanded. Why didn’t I invite distant friends to dinner over Zoom before? It was technologically possible but never occurred to me. Maybe, as virus-related restrictions ease and eventually end, we will keep in better contact with people far away. Perhaps one good thing to come out of this horrible pandemic will be a stronger sense of how – in a very real way – our wellbeing is dependent on our connections with others. Lisa Feldman Barrett is a professor of psychology at Northeastern University, Massachusetts, and author of Seven and a Half Lessons About the Brain