Computerised brain implant relieves pain in rats

The experiments carried out by the team are said to offer a blueprint for the development of brain implants to treat pain and other brain-based disorders, such as anxiety, depression, and panic attacks.

In their study, which is published in Nature Biomedical Engineering, the team showed that device-implanted rats withdrew their paws 40 per cent more slowly from sudden pain compared with times when their device was turned off.

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According to the study authors, this suggests that the device reduced the intensity of the pain the rodents experienced. In addition, animals in sudden or continuous pain 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.

Researchers said the investigation is the first to use a computerised brain implantto 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, the study authors said.

"Our findings show that this implant offers an effective strategy for pain therapy, even in cases where symptoms are traditionally difficult to pinpoint or manage," said senior study author Jing Wang, MD, PhD, the Valentino D.B. Mazzia, MD, JD Associate Professor in the Department of Anesthesiology at NYU Langone Health.

Chronic pain impacts around a quarter of adults in the United States, but safe and reliable treatments have proven elusive, said Wang.

Computerised brain implants, previously investigated to prevent epileptic seizures and control prosthetic devices, may avert issues associated with opioid use for pain relief. The 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 automatically identifies electrical patterns in the brain closely linked to pain. When signs of pain are detected, the computer triggers therapeutic stimulation of the prefrontal cortex to ease it.

Wang said that since the device is only activated in the presence of pain, it lessens the risk of overuse and any potential for tolerance to develop. Unlike opioids, the implant does not offer a reward beyond pain relief, so the risk of addiction is minimised.

As part of the study, the researchers installed electrodes in the brains of dozens of rats and then exposed them to carefully measured amounts of pain. The animals were closely monitored 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.

According to the study authors, the implant accurately detected pain up to 80 percent of the time.

"Our results demonstrate that this device may help researchers better understand how pain works in the brain," said lead study investigator Qiaosheng Zhang, PhD, a doctoral fellow in the Department of Anesthesiology, Perioperative Care and Pain at NYU Langone. "Moreover, 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, but cautioned that the technology is not yet suitable for use in people. To that end, plans are underway to investigate less-invasive forms with potential to be adapted for human use.