Brain implant helps to relieve chronic pain
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A computerised brain implant has effectively relieved short-term and chronic pain in rodents, a new study has found. The researchers behind the project said called it a ‘blueprint’ for the development of brain implants to treat pain syndromes and other brain-based disorders.
The study, conducted by investigators at New York University’s (NYU) Grossman School of Medicine, showed that device-implanted rats withdrew their paws 40 per cent more slowly from sudden pain when the device was on compared to when it was turned off suggesting that it helped to reduce the intensity of the pain experienced.
Animals in sudden or continuous pain also spent about two-thirds more time in a chamber where the computer-controlled device was turned on than in a chamber where it was not.
The researchers said the investigation is the first to use a computerised brain implant to detect and relieve bursts of pain in real-time. The device is also the first of its kind to target chronic pain, which often occurs without being prompted by a known trigger, they added.
“Our findings show this implant offers an effective strategy for pain therapy, even where symptoms are traditionally difficult to pinpoint or manage,” said study author Dr Jing Wang, associate professor.
According to Wang, chronic pain is estimated to affect one in four adults in the US, yet until now, safe and reliable treatments have proven elusive. Particularly for pain that keeps coming back, current therapies such as opioids often grow less effective over time as people become desensitised to the treatment. Drugs, such as opioids, activate the reward centres of the brain to create feelings of pleasure that may lead to addiction.
Computerised brain implants, previously investigated to prevent epileptic seizures and control prosthetic devices, may avert many of these issues, Wang said.
The technology, known as a closed-loop brain-machine interface, detects brain activity in the anterior cingulate cortex, a region of the brain that is critical for pain processing. A computer linked to the device then automatically identifies electrical patterns in the brain closely linked to pain. When signs of pain are detected, the computer triggers therapeutic stimulation of another region of the brain, the prefrontal cortex, to ease it.
Since the device is only activated in the presence of pain, it lessens the risk of overuse and any potential for tolerance to develop. Because the implant offers no reward beyond pain relief, as opioids do, it minimises the risk of addiction.
As part of the study, the researchers installed tiny electrodes in the brains of dozens of rats and then exposed them to carefully measured amounts of pain. They closely monitored the animals for how quickly they moved away from the pain source. This allowed the investigators to track how often the device correctly identified pain-based brain activity in the anterior cingulate cortex and how effectively it could lessen the resulting sensation.
“Our results show this device may help researchers better understand how pain works in the brain,” said lead study investigator Qiaosheng Zhang. “It may allow us to find non-drug therapies for other neuropsychiatric disorders, such as anxiety, depression, and post-traumatic stress.”
Zhang added that the implant’s pain detection properties could be improved by installing electrodes in other regions of the brain beyond the anterior cingulate cortex. He cautioned that the technology is not yet suitable for people, but plans are underway to investigate less invasive forms with the potential to be adapted for human use.
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