Doctors normally use MRI to look inside the body to examine organs and tissue, for instance to find tumors and other abnormalities. Now, biological engineers in the US want to adapt the scanning technology to work on a much smaller scale. They want to use magnetic resonance imaging (MRI) as a "molecular imaging" tool to see genes at work in living brains and find out what effect they have on cognitive processes like memory and learning. The team working on this is at Massachusetts Institute of Technology (MIT).

Their leader, Alan Jasanoff, an associate professor of biological engineering, says:"The dream of molecular imaging is to provide information about the biology of intact organisms, at the molecule level. The goal is to not have to chop up the brain, but instead to actually see things that are happening inside."MRI uses magnetic fields and radio waves to interact with protons in the body. This interaction produces detailed images of the insides of the body. Functional MRI allows neuroscientists to see which parts of the brain are active during various tasks by "seeing" where the blood flows. When scanning other organs, doctors sometimes use magnetic "contrast agents" so the tissue they are investigating stands out more clearly. What the MIT team has done is develop an artificial "reporter gene" that switches on and off to signal certain events in the body - rather like the indicator light that flashes on the dashboard of a car.