Using transcranial Direct Current Stimulation (tDCS) to improve cognitive abilities.
Abnormal Brain Network of Cognitive Impairment in Parkinson’s Disease
Deep brain stimulation is a treatment to reduce the tremors, stiffness and slowness associated with Parkinson’s disease by placing electrodes that deliver electrical currents deep inside the brain, reactivating areas where the circuitry for motor control is damaged.
Although effective in reducing these motor symptoms, deep brain stimulation requires surgery and does not improve the reasoning, judgment and memory deficits that Parkinson’s can also produce.
At the University of Manitoba, neuroscientist Ji Hyun Ko is exploring the use of another, less invasive form of brain stimulation to treat those cognitive symptoms. He’s focusing on the damaged circuits in an area deep within the brain called the caudate nucleus, which researchers believe is key to cognition.
“Even before they develop dementia, a lot of people with Parkinson’s have mild cognitive problems that hinder their daily activity,” says Ko, who first trained as an electrical engineer. “Although it may be milder than dementia, it can cost people their job.”
The caudate region of the brain is difficult to reach without invasive surgery – but it may be possible to stimulate the neurons inside it that aren’t firing properly by treating nearby regions.
Using a portable, relatively inexpensive battery-powered device called transcranial Direct Current Stimulation (tDCS), Ko attaches electrodes to deliver an electric current on the surface of the brain in areas connected to the caudate. The quick, painless procedure is designed to excite or reactivate brain cells and networks of cells.
“Parkinson’s disease is about circuits. That to me was very interesting, because I can model the problem – and as an electrical engineer, if I can model the problem, I can solve the problem as well.”
“It’s based on the theory that when neurons fire together, they wire together,” Ko says. “It’s like muscle. When you use these neurons more, the connections between the two different brain regions get stronger.”
If the caudate is better connected, Ko believes it will function better.
Using brain scans before and after people are treated with tDCS, Ko can see that the technique does stimulate the regions he’s targeting. His preliminary research also indicates the cognitive abilities of people with Parkinson’s disease improve after treatment.
Now Ko will increase the length of time people with Parkinson’s get treated with tDCS to see if their cognitive abilities improve even more, and to track how long those improvements last.
If this treatment proves successful, Ko hopes it will lead to relatively inexpensive, accessible and personalized approach to Parkinson’s treatment.
Using brain imaging, doctors and researchers could determine what regions of the brain are most affected in individuals and adjust their placement of electrodes during tDCS treatment.
“Maybe there are individuals whose problem is not caudate connectivity,” Ko says. “Some patients may need to be targeted for different brain regions.”
Ko changed course from electrical engineering to neuroscience when an undergraduate course in neurobiology opened his eyes to the similarity between electrical circuits and the brain. Then he learned about Parkinson’s.
“Parkinson’s disease is about circuits,” he says. “That to me was very interesting, because I can model the problem – and as an electrical engineer, if I can model the problem, I can solve the problem as well.”