Raphael Thys
We all hate it when a migraine creeps up on busy days, and one is left with no choice but to pop a medication and wait for the pain to subside. But if all goes well, a brain implant in the future will stop a migraine attack before it even hits, and we have the researchers at New York University (NYU) to thank for it.
Results of the study were published in Nature Biomedical Engineering.
The implant, in its early experimental stage, was tested in rats. It might still be far away from medical use but is an important achievement in pain management. For starters, this is the first time an implant is actually doing something to arrest the signal it is receiving. So, far, implants have been used to send texts, give tactile feedback, and even allow monkeys to play games using their minds.
What the researchers at NYU have managed is to use use the signal to anticipate pain and then use another system to quell it. This might seem just logical but gets a lot more difficult when you try to get it to work inside the brain.
To anticipate pain, the team implanted electrodes in the anterior cingulate cortex (ACC) region of the brain that is known to process pain signals. To dampen the pain, they installed an optical fiber cable in the prelimbic prefrontal cortex (PFC) region. Previous studies have shown that activating neurons in the PFC region reduces pain signals in rats as well as primates. When the ACC receives pain signals, the implant directs the optical fiber to activate and shines a light on the neurons of the PFC region, activating them. The pain is detected and attended to in real-time.
But how does a rat tell you that its pain has subsided? Well, it doesn't.
To test if the implant worked, researchers exposed the rats to acute mechanical pain, such as a pinprick to their paws, that should evoke immediate responses. Once the implant was on, the rats withdrew their paws 40 percent slower. They also allowed rats the option to move between two chambers. In one, the implant worked only in response to a pain stimulus. In another, it just turned on randomly. The rats chose to spend more time in the former chamber, suggesting that the treatment was working.
The work is also helpful in demonstrating alternate methods of pain management. Long-term use of opioids for pain relief also results in addiction to prescribed drugs. "Since the device is only activated in the presence of pain, it lessens the risk of overuse and any potential for tolerance to develop," said associate professor Jing Wang, the vice-chair for clinical and translational research at NYU and one of the authors of the study. He added, "Unlike, opioids, the implant offers no reward beyond pain relief, minimizing the risk of addiction".