It has been known since the 1960s that some sounds and music can relieve stress and pain. Since then, music therapy has been used in dental operations and post-operative treatments, among other things. A team led by Wenjie Zhou from the University of Science and Technology of China now being studied in mice. the Results have appeared in the journal Science.
Volume is more important
In order to be able to find out whether and how pain can be alleviated by music, the experts first elicited a painful inflammatory reaction in the hind legs of the mice. They then exposed the animals to different acoustic stimuli. These included classical music, chaotic tone sequences and white noise. Music and noise were also used at different distances and volumes.
It turned out that it was not the type of sounds that had an impact on the mice’s perception of pain. The decisive factor was the volume in connection with the ambient noise. If the volume is regarding five decibels (dB) – comparable to a whisper – above the noise from the environment, there is a pain-relieving effect. This lasted for up to two days following turning off the music and white noise. On the other hand, if the volume was ten, 15 or more decibels higher, this effect did not occur.
Connection between auditory center and thalamus
With the help of fluorescent proteins, the researchers visualized those areas in the mice brain that react to the perception of pain and musical stimuli. They identified neural networks between the auditory center in the rodent’s temporal lobe and the Thalamus.
The thalamus is a kind of stimulus filter in the brain that only forwards the currently most important information to the cerebral cortex (cortex). This includes pain. If the neuronal networks discovered by the researchers are activated by sounds, this reduces the transmission of pain-related stimuli.
Potential for new pain therapies
According to the pain experts Rohini Kuner and Thomas Kuner from the University of Heidelberg, which publishes the study results in an accompanying Comment – also in the journal “Science” – the current findings open up new possibilities for pain therapy that are less dangerous than the use of opioids and other painkillers.
“Music and natural sounds have a positive effect on mood, relieve stress and relax the body. It is not unreasonable to think that these factors also underlie pain relief,” explain Rohini and Thomas Kuner. In order to make precise statements for human medicine, further investigations are necessary, because: “It is still unclear how animals perceive music,” the two clarify.
According to Yuanyuan Liu, co-author of the study, human brain imaging showed that there are likely similar areas to those found in the mouse brain. However, the results of the study should be treated with caution, as Kuner and Kuner emphasize: “Some noises can cause symptoms such as headaches or intensify them.” This is also the case with phonophobia – the fear of certain noises – which is common associated with migraines.
