Those of us who remember the loopy ’80s—here’s Buzzfeed’s 50 things only ’80s kids understand—recall the PSA in which a metaphorical egg sputtered in a pan as a voice intoned, “This is your brain on drugs.” The spot aimed to keep us from the drug pushers who hung out by the back door of the cafeteria, and who now mostly work in hedge funds.
But as we shake off winter, we await the promise of what can best be described as our brains on spring. Or as Robin Williams put it, “Spring is nature’s way of saying ‘let’s party.’” Is that just our emotions at work? Maybe, since our emotions are nothing more than stimulated neurological pings, and rational thought and emotional response are based on different aspects of brain chemistry.
Scientists don’t like maybe, so they’ve been digging deeper into why spring brings us the joy it does. They’ve known for a while that as the seasons turn our moods alter; our immune systems and gene expressions change; cognitive function is different; even the way we perceive color changes. No wonder we feel like running down the street singing Broadway show tunes.
A landmark 2016 study by the National Academy of Sciences found a “complex impact of season on human function.” For tasks involving working memory, performance was the highest in spring and the lowest in fall. For sustained attention tasks, summer was the best and winter was the worst.
We have evolved over millennia, but the suprachiasmatic nucleus, which controls the calendar in our brain, hasn’t changed. This tiny little guy sits inside the hypothalamus, where it gets input from photosensitized cells in the retina. It regulates many different functions of the body’s 24-hour cycle, including circadian rhythms, and is the dashboard for spring fever.
It’s worth noting that the SCN, as it is affectionately called, only has 20,000 neurons. The entire brain has about 100 billion neurons, which goes to show you that small numbers can have outsize impact — and when someone gives you a piece of their mind, which piece really matters.
Dogs have the SCN too, so they respond to the same spring stirrings we do; some Polish veterinarians found that the melatonin level of huskies peaked in the winter — when they needed more sleep — dropped in March, and were lowest in June.
Those findings align with a study published in February. Lihua Sun, a postdoctoral researcher at the University of Turku in Finland, was the lead author of the work, which showed that the duration of sunlight influences opioid receptors in the brain that impact mood. The number of those receptors vary depending on the time of year; more sun, up to a point, leads to more production of the neurotransmitters that reduce anxiety and depression. Sun, the researcher, theorizes that the phenomenon explains why the shorter days of winter lead to seasonal affective disorder, or SAD, and that the findings could lead to a treatment. To sum up both the situation and the science: Mr. Sun hasn’t cured SAD, but he’s working on it.
So, is there anyone who isn’t buoyed by spring? Try the mordant Dorothy Parker, who wrote: “Every year, back comes Spring, with nasty little birds yapping their fool heads off and the ground all mucked up with plants.”
Parker, of course, had a well-documented penchant for brown liquor, and her churlishness certainly seems to capture the worldview of someone struggling through a “morning after.” In other words, she probably would have had a different outlook if she could’ve gotten her brain off Scotch and on spring.