I visit Bettina Schwab, lead researcher and expert in brain stimulation. PhD candidate Maud Bosman en Masters' student Lara van Bergen fit me with an electrode cap and attach sensors to my hand. It feels uncomfortable, it doesn't go smoothly at first, but eventually everything is in place. Then the pilot experiment begins.
How your brain controls your muscles
Every movement starts as an electrical signal in your brain. That signal travels through your nervous system to your muscles, where motor units do the work: small units that each control a different part of the muscle, dozens at a time, in precise coordination.
In Parkinson's disease, that coordination breaks down. Signals arrive incorrectly, too late, or not at all. The result is tremors, stiffness and loss of control over your own body. Deep brain stimulation can help: a surgical procedure in which electrodes are placed deep inside the brain to modulate these signals. Bettina wants to know whether non-invasive brain stimulation can help to find out about the mechanism of deep-brain stimulation. I'm the test subject.
Sine waves or pulses
Bettina tests two types of electrical signals: sine waves, most commonly used in non-invasive brain stimulation, and shorter pulses. The question is whether the shape of the signal affects how the motor units in the spinal cord respond, and whether the motor neurons become synchronised or not.
That's what they measure via my hand. Meanwhile, I notice it tingles, it gets warm, and sometimes it gets a bit uncomfortable. How much pain varies from person to person, and that is also part of the experiment.
Beyond Parkinson's
Brain stimulation is about more than one disease. It can potentially play a role in rehabilitation after a stroke, in the development of brain-computer interfaces and in fundamental research into how the brain and muscles work together. That makes this research relevant to anyone who might one day be affected by neurological conditions, not just people with Parkinson's disease.
