New Hope for People Living with Chronic Pain

Researchers of a study published in Nature Neuroscience are investigating how severe pain can cause nerve damage that can permanently alter the brain and result in chronic pain.

When a person experiences severe pain, such as breaking or shattering a bone, the pain is felt throughout the body because there is a full network of receptors running from the site of the injury, through your nervous system, along the spine and into the brain that reacts to tell you how much pain you are feeling. Although this system goes into high alert when the injury occurs, it usually resets after the injury site heals. However, sometimes, the system doesn’t reset, and even though the injury has mended, nerve damage has caused your brain to be permanently altered. Essentially, you still feel neuropathic pain, even after your physical injury has healed.

“It’s a terrible situation for many people living with chronic pain, because there is often very little that works for them to control their pain,” says Zamponi, senior associate dean (research) and a professor in the departments of Physiology & Pharmacology and Cell Biology & Anatomy at the CSM in a press release. “This doesn’t just impact people who have experienced peripheral nerve damage. There are cases of people having a stroke and are experiencing severe pain afterward in another part of their body. It may also explain why some people who have lost a limb can still feel pain in the limb even though it’s no longer there.”

A research team with the Cumming School of Medicine’s Hotchkiss Brain Institute (HBI) and researchers at Stanford University, California, headed by Dr. Gerald Zamponi, PhD, have been investigating which brain circuits are changed by injury, in order to develop targeted therapies to reset the brain to stop chronic pain.

In collaboration with Dr. Junting Huang, PhD, and Dr. Vinicius Gadotti, PhD, co-first authors on the study, along with Dr. Zizhen Zhang, PhD, the team used optogenetics, which allow scientists to use light to target and control individual neurons, in animal-models to asses neuron connections in the brains of mice.

By utilizing this tool, researchers can map a pathway depicting which neurons are communicating with each other to process a pain signal and then communicate this information all the way back through the spine where painful stimuli are first processed.

Understanding How the Brain Rewires

“We’ve known that certain parts of the brain are important for pain, but now we’ve been able to identify a long range circuit in the brain that carries the message and we’ve been able to show how it is altered during chronic pain states,” says Zamponi who is also a member of the CSM’s Alberta Children’s Hospital Research Institute. This new understanding of the pain signaling circuit may allow scientists to develop new drug therapies and targeted brain stimulation treatments to address chronic nerve pain, and which may provide chronic pain relief.

“If you understand how the brain rewires itself, you can interfere with that and you can restore it. That’s important,” says Zamponi. “If you think about it, there are some drugs you don’t want to give to kids who have chronic pain. What if you could non-invasively stimulate certain brain regions or inhibit them, and bring pain relief that way? I think it would be a tremendous, alternative approach to taking drugs.”