Brandon LeMusic is a drug, and in the age of the coronavirus, I’m taking a lot of it. Chores, exercise, and work: all soundtracked. While my aural appetite has always been voracious, usage logs I acquired from my music streaming service revealed a substantial increase in quarantine listening. In the 9 months preceding the pandemic, my play-time averaged 3.05 hours per day; in three months of lockdown, I logged 4.67 hours per day, a 1.53-fold (53%) increase. Steeped in sound, I was thinking about the neuroscience surrounding music more than ever. What were all these blips, beeps, swells, and strums doing to my brain? How were my music selections impacting my emotions and behavior?
This is your brain on music: Aroused, emotive, and rewarded. These are not novel states – the same types of brain signaling molecules – neurotransmitters such as serotonin and dopamine – mediate orgasm, emotional response to a Frida Kahlo work, and the effects of cocaine. But music’s effects are perhaps more multifaceted and far-ranging, with scientific evidence describing impacts on several domains of human neurophysiology controlled by a constellation of interconnected brain regions. What starts in the auditory cortex soon ripples across the entire neural landscape, including the visual and motor cortices. These activity patterns are dependent on whether one is listening versus performing, as well as their exposure to musical training. Dynamic regulation of such elaborate activity patterns was demonstrated in a study of trained composers. In these subjects, coordination of activity between brain regions shifted during the act of music creation to shut out visual and motor connectivity, instead redirecting traffic to connect regions likely important for planning upcoming notes within emotionally resonant motifs.
What unique brain phenomena generate the tangible rewards provided by Debussy’s Claire de Lune or Aphex Twin’s Alberto Balsalm? One way to peek behind the curtain is through brain imaging technologies like functional magnetic resonance imaging (fMRI), which localizes brain activity, and positron emission tomography (PET), which can connect activity patterns to specific chemical processes. A recent study combined the two approaches to explore the mechanisms of musical pleasure. Researchers screened for individuals who reliably experienced “chills to instrumental music”, and played their favorite tracks while imaging their brains. As musical tension mounted, dopamine activity accumulated in one of the brain’s key relay stations called the caudate nucleus, leading to a larger dopamine spike in the nearby nucleus accumbens that accompanied the song’s emotional and chill-inducing sonic climax. In short, musical rewards play out in multiple brain areas within the same circuitry that evolved to motivate and reinforce survival behaviors such as eating food and having sex. No wonder that bass drop hits so hard.
Musical euphoria experienced as “thrills and chills” also plays out within known pleasure pathways to fulfill reward. These circuits are major sites of action for opioids: the painkillers infamous for their lethal and addictive power. While the release of the brain’s natural opioids in response to music has not been directly measured, one study found that music reduced the need for painkillers following surgeries, which has inspired the exploration of using music as an adjunctive therapy to reduce dependence on potentially addictive opioid-based pain management. Another study showed that blocking the μ-opioid receptor with the drug Naltrexone blunted both positive and negative emotional responses to music, showing that musical stimulation engages well-characterized hedonic circuitry. Thankfully, dosing music does not seem to be prone to abuse. I was relieved to find scant evidence for musical addiction – somewhat puzzling given such notable effects on the motivation, reward, and pleasure circuits typically hijacked by addictive chemicals and behaviors.
The brain’s ability to boogie didn’t evolve overnight. Natural selection has primed us to adaptively respond to ambient sound and produce complex intraspecies communication to enhance survival and fecundity. Accordingly, humans aren’t the only species with aural affinity: rats exposed to melodic auditory stimulation show coordinated dopamine and serotonin neurotransmitter activity in cortical regions linking reward and motor control, and songbirds clearly have a knack for applying auditory cues to vocal learning. Millions of years of evolution shaped and honed the auditory system’s neural circuitry, so it makes sense that music penetrates even the deepest and most primitive regions of our “lizard-brains” like the brainstem and midbrain. These areas are vital in establishing fundamental physiological and homeostatic rhythms using noradrenaline neurotransmitters, among others. Processes such as heart rate, blood pressure, body temperature, muscle tension and skin conductance are all subject to musical modulation within these structures. This may not come as a surprise, since many of us use music to enhance our execution of all kinds of activities, from exercise to open heart surgery. Just take care to prune your playlist carefully, since musical tweaks on physiology scale with tempo and intensity.
Evolutionary refinement of our responses to music occurs when natural selection acts on genes. Might genetic variation affecting brain chemistry or circuitry involved in auditory pathways explain why some of us seem to have ears and minds that riff from a different songbook entirely? Consider a musical savant like Joey Alexander, who, by age-8, was skilled enough as a jazz pianist to wow Herbie Hancock. Can genetics explain how a kid in Bali taught himself to play a notoriously difficult and experience-dependent style of music just by digging through his parent’s vinyl collection and noodling along on a miniature electric keyboard? Like every other complex trait, musical ability is sure to be a complex interplay between nature and nurture, but even accounting for training and environment, people may be hard-wired to create, perceive, and respond to music differently. Absolute or “perfect” pitch, for example, correlates strongly within certain families and population groups. Leveraging modern genetic techniques such as genome-wide association studies against the natural spectrum of human musical traits is beginning to connect genetic elements to known neurophysiological processes to hint at their underlying molecular mechanisms and heritability. Associations between “musical creativity” and several genomic regions related to serotonin neurochemistry are tantalizing prospects that could explain some degree of musicophilia, but require experimental follow-up to be validated. A diversity of emerging evidence linking genetic variation to auditory traits demonstrates how, as with other drugs, one’s response to music may vary.
Music is not just a drug, but a wonder-drug. In an era where mental health has rapidly become a global crisis, perhaps the only obvious prescription is more cowbell. The diversity and complexity of auditory stimuli are effectively infinite, and when combined with the physicality of musical creation and performance, it becomes clear how music can tap into nearly every region and neurochemical modality of our impressively interconnected brains. So blast Bach for the babies and crank Kendrick for the crusty – we could all benefit from a few more songs in our synapses.
Peer edited by Kayla Goforth and Breanna Turman.