Sounds—including music and noise—can relieve pain. A study is getting to the bottom of the previously unknown neuronal mechanisms behind it.
That sound waves It has been known for a long time that pain can be effectively suppressed. However, it is still unclear what triggers the pain-relieving effects of music or noise. Zhou et al. demonstrated using a variety of methods in mice that the auditory cortex is functionally linked to regions attached to the Nozizeption, i.e. the perception of pain, are involved. They showed that the pain sensitivity of mice might be reduced by sounds of a certain intensity.
As the basis of their im Science Magazine In the published study, the research group refers to studies on humans carried out more than 60 years ago: According to this, music and other types of noise can relieve acute and chronic pain. The sounds had a pain-relieving effect during dental and medical interventions contractions and confinement just like Krebs. Like the brain this analgesia generated, but was previously unclear.
Of the Paw Test
The new study, conducted by teams from the University of Science and Technology of China and Anhui Medical University, is the first to examine and manipulate in detail the neural structures believed to be associated with musical pain relief.
The research group first used different models of pain induction in mice: By Capsaicin-Injections as well as an operative It is bound of the Tibial nerve und Common peroneal nerve (Spared Nerve Injury) wurden neuropathic pain and induces inflammation of the paws. The scientists put non-infectious viruses with fluorescent proteins were coupled through the opened calvaria into the brain of the mice. Three weeks later, they were able to identify brain areas using fluorescence signals originating from the AcxGlu or MGB-Glu neurons of the auditory cortex, as well as from the Area preoptica (PO) and des ventral pallidum (VP) originate, trace. This revealed previously unexplored areas using calcium as an in-vivo single-cell representation, i.e. at the cell level. In plain language: Structures that were previously only suspected through imaging in humans that they play a special role in acoustic analgesia might now be observed in detail.
In addition to photometric investigations of specific calcium signals, the pain reaction of the animals was also determined. To do this, the mice had to use their paws to bend increasingly stronger filaments with sufficient force. The thread from which the mice quickly withdrew, twitched or licked their paw was set as the threshold for the pain response. If there was no positive pain response, a heavier gauge suture was used and the measurement was repeated five times to obtain an average threshold. The thermal nociceptive threshold was determined using the Hargreaves test. After habituation, the paw was irradiated with laser heat and the paw withdrawal latency was measured.
Music makes you less sensitive
The mice with painful paws were exposed to three types of sounds: a pleasant piece of classical music, an “unpleasant” rearrangement of the same piece, and white noise. White noise describes a monotonous noise that is supposed to help the brain to ignore background noise and suppress ambient noise.
Surprisingly, the scientists found that all three types of sounds, when played at a low signal-to-noise ratio (SNR) (regarding as loud as a whisper; 5 decibels), reduced the mice’s sensitivity to pain. The mice didn’t really care whether the noises were melodic or beautifully composed. Only the intensity of the three sounds seemed important. This ensured that the mice only withdrew their paws when subjected to greater stress, compared to mice without musical accompaniment. Louder sound waves had no effect on the pain reactions of the animals. The researchers suspect that the pain relief is not due to stress reduction or distraction, as the pain-relieving effects lasted for at least two days following the sounds were withdrawn.
Viral tracing and microendoscopic calcium imaging showed that sounds with low SNR intensity glutamaterge Inputs from the auditory cortex (AcxGlu) to the posterior (PO) and ventral thalamic (VP) nuclei were inhibited. So the sounds caused pain relief by blocking the connection between the auditory cortex and the thalamus. To examine this effect more closely, the researchers manipulated this circuit using chemical and optical methods. Artificial activation of the circuit reversed the sound-induced analgesia.
Effect of music not yet clear
It’s unclear whether similar brain processes occur in humans, or whether other aspects of sound, such as harmony or melody, might be important in human pain relief. The reported results might provide scientists with a starting point for studies to determine whether findings from the animal kingdom can be extrapolated to humans, and might ultimately aid in the development of complementary methods of pain management.
However, caution is advised as the interaction between sound and pain is a double-edged sword. Certain sounds can even trigger or increase pain, such as the Phonophobiewho at migraine frequently occurs.
| follow the channel Thrill for more neurology topics. consequences Are you also interested in news regarding mental health? Discover here the appropriate channel head thing. |
Image source: Vlah Dumitruunsplash
