New Brain Network Discovery Could Transform Parkinson's Care

Scientists have uncovered a game-changing explanation for why Parkinson's disease affects so much more than just movement.

Researchers publishing in Nature today found that Parkinson's disrupts a brain network called SCAN (somato-cognitive action network) that bridges thoughts and actions throughout the entire body. This network, only discovered in 2023, controls everything from walking to digesting food to thinking clearly.

For nearly a century, doctors believed the brain's primary motor cortex was simply a map of body parts, each controlling its corresponding limb or organ. But neurologist Nico Dosenbach at Washington University in St. Louis noticed something odd: when people moved their mouth in brain scanners, multiple unexpected areas lit up across the motor cortex.

His team discovered that interspersed between body-specific areas are nodes of a network that coordinates higher-level planning for movement. The motor cortex wasn't just following orders. It was helping plan and guide action.

Neuroscientist Hesheng Liu in Beijing had been puzzling over strange brain patterns in Parkinson's patients for a decade. When he saw Dosenbach's SCAN discovery, everything clicked into place.

Liu's team analyzed brain scans from 863 people with Parkinson's and healthy individuals. People with Parkinson's showed abnormally high connectivity in SCAN regions, and those with stronger connectivity experienced worse symptoms.

Here's where it gets exciting: existing treatments like medication and brain stimulation already reduce this excessive connectivity. The more a treatment normalized someone's SCAN network, the more their symptoms improved.

Why This Inspires

This discovery explains mysteries that have puzzled doctors for generations. Why do Parkinson's symptoms worsen under stress but improve while listening to music? Why does the disease affect sleep, blood pressure, and digestion alongside movement? The answer is SCAN connects all these systems.

"Parkinson's is not just a movement problem involving one body part," says Michael Okun, medical director of the Parkinson's Foundation. "This study shows it is a whole-body brain network disorder that links movement, thinking, arousal and internal body control."

The research showed that brain stimulation treatments worked better when doctors specifically targeted SCAN regions rather than other areas. This precision could make existing treatments more effective for the 10 million people worldwide living with Parkinson's.

Todd Herrington, a neurologist at Massachusetts General Hospital, called the findings "extraordinary." Scientists still need to determine whether dying brain cells cause SCAN disruption or vice versa, but either way, the network offers a new target for treatment.

For the first time, doctors can see exactly which brain circuit goes wrong in Parkinson's disease and measure how well treatments fix it.