

Smoking during a brain scan is not easy. Why would you want to? Because functional magnetic resonance imaging (fMRI) allows researchers to observe activity in the brain, and doing so while smoking tobacco or pot could enhance our understanding of addiction and how to treat it.

But during an MRI, the head must remain completely still. In the narrow bore of a superconducting magnet, there isn't much room to maneuver a cigarette or eat a pot brownie either. Smoke raises a second set of concerns. At the very least, it will stink up the lab. Perhaps, it could even damage the expensive machine.

So Blaise Frederick at Harvard Medical School built a device that delivers smoke into the narrow confines of a scanner. His colleagues, Kim Lindsey and Liz Ryan, tested it out on nine volunteers at McLean Hospital. They described their work in the May issue of Pharmacology, Biochemistry, and Behavior.

Since that project was completed, Lindsey has used the same equipment to study the neurological effects of tobacco. Last Friday, Scott Lukas, the ringmaster for these studies and director of the Behavioral

Psychopharmacology Research Laboratory was informed that he and Frederick will receive a grant to conduct further studies with marijuana.

Displaying skills that would put MacGyver to shame, Frederick constructed a makeshift water pipe inside of a picnic cooler, then ran

2.4 meters of tubing to a plastic facemask that rests inside of the scanner. Since the mask is made from materials that are not magnetic, it will not interfere with the imaging.

To be sure that the contraption can get people high, Lindsey and her associates asked nine volunteers to inhale smoke from a marijuana cigarette with exactly 3.51 percent THC, then checked to see how much of the drug made it into their blood. Using the mask, the subjects got almost as high as if they had puffed on a joint directly. The researchers suggested using stronger weed to achieve more realistic effects.

Most important, the plastic facemask did not interfere with the scanner. While the volunteers were smoking, they were given a visual stimulus. Several sharp images of activity in their visual cortices showed that the Harvard scientists can credibly say, "This is your brain on drugs."