Wide awake, a rat placed inside a typical brain scanner is too active for images to be recorded. For studies of drug effects on behavior, anesthesia is no alternative. So, Craig L. Woody of Brookhaven National Laboratory in Upton, N.Y., and his colleagues there and at Stony Brook (N.Y.) University are developing a miniature positron-emission tomography, or PET, brain scanner that moves with the rat.
The blocks of this mock-up represent gamma-ray detectors. After a radioactively tagged drug or nutrient is injected into the animal’s blood, the functional ring will sense radiation from brain regions that use those molecules, Woody says.
Rats seem comfortable in the mock-up, which is suspended from a counterbalanced tether, he adds. Tests of a working ring are expected by year’s end.