What happens to your brain when the music of Def Leppard, Frank Sinatra or even Michael Bolton blasts through a speaker and fills your head?

Obviously, there are different reactions and feelings depending on your musical tastes and tolerance for a particular genre of music.

Daniel Levitin, a McGill University professor often referred to as the "rock 'n' roll doctor" for his music-industry work with Steely Dan, The Grateful Dead and Stevie Wonder, has studied the effect of music on the brain.

His analysis? There's a whole lot of shakin' going on inside when music is being played, he's concluded. And, he adds, it also has something to do with the link between our own development and the history of music.

"The parts of the brain that are activated by the nature of the activation teaches us something about the evolutionary history of the brain and about the evolutionary history of music. That's the exciting part," explained Levitin, 50, in a recent interview.

"It's sounds like an outlandish claim, but we find that when you're listening to music lying (hooked up) to a brain scanner, the part of the brain that would normally tap your foot or clap your hands ... that part of the motor cortex is active, even while you're lying perfectly still and not moving.

"What this suggests is an ancient evolutionary link between music and movement. If you put together a story from what we know about anthropology and development of the species, for tens of thousands of years music was practised very differently than it is today. It was always the case that music and dance co-occurred, but now we sit around with earbuds and listen to music and attend concerts where people play for us while we sit perfectly still," he explained.

He said when we find something pleasurable, it's often the case that it serves some evolutionary function. "It feels good because we get a rush of neuro-chemicals associated with the activity because those of our ancestors who enjoyed doing it had some advantage."

Levitin studied cognitive psychology/cognitive science at Stanford University, where he received a bachelor of arts in 1992. He's also the author of This Is Your Brain On Music: The

Science of Human Obsession, which spent six months on The New York Times Bestseller List.

Levitin also enjoyed a previous career in the music industry. In the 1970s, Levitin worked for M&K Sound in the United States and assisted in designing a commercial satellite and subwoofer systems that were used by Steely Dan on their album Pretzel Logic.

In the 1980s, he worked as a consulting record producer and engineered records by Santana and the Grateful Dead, as well as producing tracks for Blue Oyster Cult and the soundtrack to the cult film Repo Man.

He will be in Ottawa tomorrow at 8 p.m. at the Canadian Tulip Festival's Celebridée series, talking about his research on music and the brain.

He said studying the brain is important because understanding how the brain functions allows us to get closer to treating people with serious brain injuries or diseases such as Alzheimer's. Since music activates every region of the brain, it serves as a "window" into the functioning of the brain, he said.

In his research lab, Levitin studies people who are hooked to brain scanners that gauge how they react to music.

"We may play music that a person likes versus music they may not prefer, to see if there are differences in activation. We may also play music that is rhythmic versus music than is not and even music people are familiar with, so there's always some sort of experimental manipulation that serves the research question we're asking," he said.

Music, he explains, is sound organized over time with variations in pitch, rhythm and timbre.

"My definition of the pleasure we derive from listening to music is that it's both esthetic and an emotional pleasure, sometimes bordering on physical pleasure."

He said music is played everywhere, whether at happy events or even sombre occasions. "People play music after death at funerals for example, or if they're just stressed out.

"But say you just had a fight with your partner are you going to listen to music to make you feel better? If so, what kind of music would you listen to and how effective do you think it would be in changing your mood?

"What we found is that people seem to be able to self-medicate with music, but not everybody. A lot of people seem to have some acquired knowledge of what kind of music it is that's going to help them at certain times of their lives," he said.