Parkinson State of Mind

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Krembil researchers discover a novel brain state that sheds new light on Parkinson disease.
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Like streets in a city, brain cells called neurons physically connect with each other to create ‘neural pathways’ capable of transmitting information between distinct regions of the brain.

More than one billion people around the world use the web mapping service Google Maps. Among its most popular features is the trip planner, which suggests the most optimal route to travel from one destination to another.

Similarly, the healthy brain depends on many networks of optimally connected routes to efficiently send and receive information. A new study by Krembil Senior Scientist Dr. Antonio Strafella reveals that the disruption of these networks may result in Parkinson disease—a neurodegenerative disorder causing changes in movement, behaviour and cognitive ability.

In the study, Dr. Strafella and his research team used a highly sophisticated imaging analysis technique called dynamic functional connectivity to visualize the brains of people with or without Parkinson disease. They found that brains switch back and forth between two states: in the first state, the brain has sparse connections, but these connections function very efficiently in transmitting information; however, in the second state, the connections are unstable despite the fact that they are highly connected.

In comparing the brain states of those with or without Parkinson disease, the researchers found that people with Parkinson disease were more likely to be in the second state. A shift in brain states from the first to the second was associated with the severity of Parkinson disease symptoms, such as tremor, slowness of movement and impaired speech.

“We are the first to identify this second brain state,” says Dr. Strafella. “Our results indicate that the brain of a patient with Parkinson disease is not very efficient and is not taking the fastest and shortest route between two points to perform a task. Our next step is to figure out what role this process plays in the evolution of the disease and how treatments to influence this brain state might help improve patients’ quality of life.”

This work was supported by the Canadian Institutes of Health Research and the Toronto General & Western Hospital Foundation. A Strafella is a Tier 2 Canada Research Chair in Movement Disorders and Neuroimaging.

Kim J, Criaud M, Cho SS, Dı´ez-Cirarda M, Mihaescu A, Coakeley S, Ghadery C, Valli M, Jacobs MF, Houle S, Strafella AP. Abnormal intrinsic brain functional network dynamics in Parkinson’s disease. Brain. 2017 Oct 5. doi: 10.1093/brain/awx233.

The study was led by Krembil Senior Scientist Dr. Antonio Strafella (pictured).