Mind Over Matter

Making the next move

November 4, 2009 – Humans are tactile animals, meaning that when we see something new or curious, our first instinct is to touch and hold it with our hands. But what controls that impulse?

Imagine a cup on the table in front of you, which you want to pick up. In order to do so, your brain must first create a signal that “plans” to reach for that cup, and then send that signal, causing your arm to move to grasp it.

Sam Musallam, an NSERC-funded researcher at McGill University, has grappled with how to transform a signal from the brain into actual movement since 2002. His work blends physics, biology, engineering and neuroscience with the goal of creating functional cybernetic prosthetics that allow paralyzed patients to live more independent lives.

It sounds like science fiction, but Dr. Musallam and his colleagues have already proven the concept in monkeys. “We trained the monkeys not to reach toward an object until instructed to, usually after a one second delay,” says Dr. Musallam. “However, in that one second delay from seeing the object to physically reaching for it, the brain creates a plan; a strategy to move.”

Using specialized equipment, sensors pick up the plan to move, or signal, which arises from the parietal cortex part of the brain. The signal is then interpreted by a computer algorithm and causes a cursor to move on a computer screen.

The project is continuing with animal testing, and progressing to a more complex environment in the computer with a newly developed algorithm to decode the brain’s reach signals.

Another focus of Dr. Musallam’s research involves implanting very small medical devices (with electrodes about the width of a human hair) directly into the brain. These devices would store a certain amount of a therapeutic chemical that needs to be administered into a specific area of the brain. “For example, in Parkinson’s patients,” he says, “a drug could be injected directly into the basal ganglia for a more focused and effective treatment.”

Currently being tested in rats, the human applications are numerous, including administering serotonin for depression, dopamine for Parkinson’s and anticonvulsants for epilepsy.

Dr. Musallam is very optimistic about the potential applications of his research.

“My goal is to have a device to be implanted in patients with neurological diseases in three years, and to have a prosthetic device for paralyzed patients in five.”