Neuronal understanding of the analgesic effects of music
Science Editor Daisy Scott discusses recent findings which reveals the neuronal mechanisms behind past understandings of the role that music holds in reducing pain
The relief of acute and postoperative pain remains a significant challenge in medicine. Studies have suggested that up to 41% of patients experienced moderate to severe pain after surgery. For a long time, drug analgesia has remained the main method of pain relief, but it does have the disadvantage of high cost and adverse side effects. Music has had a place in pain-relief therapy in many cultures for centuries but the understanding of the neural mechanisms behind its analgesic effects are only just starting to be understood. In comparison to drug therapy, music has several advantages including being free of side effects and high performance-cost ratio.
Up to 41% of patients experienced moderate to severe pain after surgery
The idea of the healing effects of music can be traced all the way back Ancient Greek culture. Music was used to ease stress, promote sleep and soothe pain. Plato considered music to be “the medicine of the soul”. Since then, there are many other cultural examples of music healing, mainly in Native American, Indian and African tribes.
Since the 1960’s, there has been scientific evidence that has proved that music, along with other forms of sound can alleviate pain. However, the neuronal mechanisms behind this was, until relatively recently, not well understood.
Research conducted at the National Institute of Dental and Craniofacial Research (NIDCR), the University of Science and Technology of China and Anhui Medical University has finally shone light onto the neural substrates underpinning musical analgesia. To understand the brain circuitry, they used non-infectious viruses with fluorescent proteins to visualise any links between different regions of the brain. In the research, mice with inflamed paws listened to three types of music – harmonious classical music, discordant classical music, and white noise. All three – when played at low intensities ~5 decibels – mitigated pain in the mice. However, when each of these were played at higher intensities, the analgesic benefits disappeared. The pain response in the mice were measured via the fluorescent proteins that followed responses in the brain.
All three – when played at low intensities ~5 decibels – mitigated pain in mice
The researchers found a route from the auditory cortex, which receives and processes information about sound, to the thalamus, which acts as a relay station for sensory signals for the body. At low-volume music, there was reduced activity of the neurons at the receiving end of the thalamus.
The findings from this study back up results from previous studies. McCaffrey et al treated 66 elderly patients with osteoarthritis by music and found music intervention could reduce pain in patients with chronic pain. This was further backed up by Huang et al who analysed the pain of cancer patients before and after musical interventions and found that 42% of patients in the experimental group had significant pain relief compared to 8% of patients in the control group. This new research is so beneficial since it gives us an insight into
NIDCR Director Rena D’Souza has said “By uncovering the circuitry that mediates the pain-reducing effects of sound in mice, this study adds critical knowledge that could ultimately inform new approaches for pain therapy”. Liu from the University of Sound and Technology of China said, “We were really surprised that the intensity of sound, and not the category or perceived pleasantness of sound would matter”.
The results from this study could give scientists a starting point for studies to determine if these results could be applied to humans and ultimately develop a safer alternative to opioids for treating pain.
