Scientists say this brain network may explain range of Parkinson’s symptoms : NPR
Parkinson’s disease impacts more than just movement. it can also affect sleep, thinking, digestion, and even a person’s sense of smell. New research suggests these seemingly disparate symptoms may be linked to disruptions within a key brain network.
Understanding the Brain’s ‘Traffic Jam’
Hesheng Liu of Changping Laboratory in Beijing notes that individuals with Parkinson’s often experience symptoms difficult to explain by motor circuit issues alone. For example, a person may walk normally but freeze when encountering a narrow space or being asked a question. Researchers at Washington University in Saint Louis previously identified a brain network, called the somato-cognitive action network – or SCAN – that connects movement and thinking.
A study utilizing MRI data from more than 800 brains revealed that in patients with Parkinson’s, the connectivity within the SCAN network is abnormally high. According to Liu, this excess connectivity causes signals to become stuck, creating what he describes as a “tunnel jammed” with traffic.
How Treatments Impact the SCAN Network
Researchers investigated how existing Parkinson’s treatments affect the SCAN network. They found that deep brain stimulation, which delivers electrical pulses to affected brain areas, immediately lowered connectivity within the network, allowing brain signals to flow more freely. Similar effects were observed with treatments including the drug levodopa, magnetic stimulation, and focused ultrasound.
Peter Strick, a neurobiologist at the University of Pittsburgh, stated that this research represents a better scientific understanding of a disease affecting approximately 1 million Americans. He emphasized that Parkinson’s is no longer viewed solely as a movement disorder, but as a condition involving multiple systems.
Beyond Tremors: The Spectrum of Parkinson’s Symptoms
Patients often report symptoms beyond the classic tremor, slurred speech, and shuffling gait. These can include chronic constipation, a reduced sense of smell, sleep disorders, memory lapses, and fatigue. Strick recalled a patient whose initial symptom was unexplained falls, initially mistaken for intoxication. These symptoms arise because the SCAN network encompasses brain areas controlling involuntary functions like heart rate, digestion, and blood pressure.
Strick explained that the body typically manages these functions automatically, but disruptions in the SCAN network can interfere with this process. Current treatments don’t fully address these issues, but future therapies may target overlooked areas within the SCAN network.
Frequently Asked Questions
What is the somato-cognitive action network (SCAN)?
SCAN is a brain network discovered by researchers at Washington University in Saint Louis that connects movement and thinking.
What happens to the SCAN network in people with Parkinson’s disease?
In patients with Parkinson’s, the connectivity in the SCAN network is abnormally high, causing signals to get stuck.
Do current Parkinson’s treatments affect the SCAN network?
Yes, treatments like deep brain stimulation, levodopa, magnetic stimulation, and focused ultrasound all appear to act on the SCAN network and lower its connectivity.
As research continues to unravel the complexities of Parkinson’s disease, could a deeper understanding of the SCAN network lead to more targeted and effective treatments for a wider range of symptoms?