Sound treatment of pain in perspective?
According to the latest research results, pain could be easily and safely treated with the help of sound in the future. Now, for the first time, the neural mechanisms by which sound reduces pain have been identified.
A new international study involving experts from the University of Science and Technology of China has investigated what exactly triggers the pain-relieving effects of music or special noises in mice. The results can be read in the journal "Science".
New effective pain management methods are needed
"We need more effective ways to treat both acute and chronic pain, and that starts with a better understanding of the fundamental neural processes that regulate pain," says Dr. Rena D'Souza, director of the Institute. National Dental and Craniofacial Research Institute involved in the study, in a press release.
New approaches to pain therapy
"By revealing the circuits involved in the pain-relieving effects of sound in mice, this study provides important information that could ultimately provide new approaches for the treatment of pain", adds the expert.
Music can ease people's pain
Human studies have shown in the past that music and other types of sounds are able to reduce both acute and chronic pain. These included pain from dental and medical procedures, labor and delivery, and even cancer, the team said.
It was not known exactly how the brain triggers this pain relief or analgesia. "Human brain imaging studies have implicated certain areas of the brain in music-induced analgesia, but these are only associations," said study author Yuanyuan Liu.
According to Liu, it is easier to probe and manipulate these circuits in animals to identify the neural substrates involved.
Examination of mice with inflamed paws
In the new study, therefore, the mice with inflamed paws were initially exposed to three types of sounds. It was nice classical music, a rearrangement of the same piece that sounded rather unpleasant, and what is called white noise.
Sound intensity affects pain response
Experts found that the animals' sensitivity to pain was reduced to all three types of sounds when played at low intensity (comparable to a whisper).
However, when the same sounds were played at a higher intensity, it had no effect on the mice's pain responses.
“We were really surprised that noise intensity played a role and not noise category or perceived comfort,” reports Liu.
Signaling pathway from the auditory cortex to the thalamus
To study which brain circuits are responsible for this effect, non-infectious viruses coupled with fluorescent proteins were used to trace the connections between brain regions, the experts explain.
The team thus identified a signaling pathway from the auditory cortex to the thalamus. The so-called auditory cortex receives and processes information about sounds. The thalamus, meanwhile, acts as a sort of relay for sensory signals, including pain.
In free-moving mice, low-intensity white noise reduced the activity of neurons at the receiving end of the pathway in the thalamus, the researchers explain.
The team also succeeded in mimicking this pain-relieving effect of low-intensity sounds through the use of light and small molecules. In contrast, activation of the pathway restored pain sensitivity in mice.
Are the results transferable to humans?
Since the study was conducted in mice, it is unclear whether comparable brain processes take place in humans. It is also unclear whether other aspects, such as harmonious or pleasant sound, play a role in pain relief.
"We don't know if human music makes sense to rodents, but it has many different meanings to humans — it has a lot of emotional components," Liu says.
The results of the study are a good starting point for future investigations in which it is now possible to check whether the results can also be transferred to humans. This could eventually lead to the development of safer alternatives to opioids for pain management, the research team hopes. (as)
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This text corresponds to the specifications of the specialized medical literature, medical guidelines and current studies and has been verified by health professionals.
Sources:Wenjie Zhou, Haitao Wang, Yu Mao, Weijia Zhang, Chonghuan Ye, et al. : Sound induces analgesia via the corticothalamic circuits; in: Science (published 07/07/2022), ScienceNIH/National Institute of Dental and Craniofacial Research: Researchers discover how sound reduces pain in mice (published 07/07/2022), NIH/National Institute of Dental and Craniofacial Research
This article contains general advice only and should not be used for self-diagnosis or treatment. It cannot substitute a visit to the doctor.