Location, location, location: the right target for deep brain stimulation


Dr. Frederic Bretzner

Dr. Frederic Bretzner

Deep brain stimulation (DBS) is a surgical treatment for the debilitating motor symptoms of Parkinson’s disease. Although the surgery relieves the symptoms in some patients, it doesn’t work well for others.

The surgery involves implanting electrodes in the brain, and then stimulating areas of the brain with an electrical current. Because of the treatment’s uneven success, some researchers, including Frederic Bretzner, wonder if the problem lies with the group of brain cells that are being stimulated. He has recently received a two-year, $90,000, Pedaling for Parkinson’s New Investigator Award from Parkinson Canada’s National Research Program to pursue this research.

Bretzner, a neuroscientist and assistant professor at Laval University, believes the pedonculopontin nucleus region in the brain is an important target for deep brain stimulation. This region encompasses two groups of neurons, whose different purposes Bretzner is investigating.

Glutamatergic neurons may incite movement, and cholinergic neurons may inhibit movement and muscle activity. If he determines which neurons do what, Bretzner’s research may give surgeons a new target for the electrodes they use in deep brain stimulation.

“Our hypothesis is that in Parkinson’s disease, there is an imbalance between excitatory and inhibitory circuits in the pedonculopontin nucleus,” Bretzner says.

He is investigating the use of photo-stimulation to activate or inhibit these groups of neurons. He hopes to show that by stimulating motor-related neurons that are dying, or by blocking neurons that are inhibiting movement, he might observe improvements in movement and posture. His work could also point to the benefits of photo-stimulation, as an alternative to deep brain stimulation.

Bretzner has always been fascinated by the potential of neuroscience to help us understand each other, he says. Although technology doesn’t yet allow us to achieve his childhood dream of reading people’s minds, his research may yet shed light on the way the brain works.

Read about other researchers recently funded by Parkinson Canada’s National Research Program.

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