RatCAP PET collar studies mollecular structures in the brain during activity: image via U.S. Department of Energy Mice and rats are extremely valuable subjects for scientific studies because their physiology is so similar to that of humans. Neuroscience, in particular, has used these small rodents to learn more about the brain and about what happens in the brain when certain behaviors and diseases occur.
Until now, the only way science had to explore the brain during activity was through positron emission tomography (PET), a very powerful method of scanning that can capture even the molecular processes of the brain. But the problem with PET scans is that animal subjects must be anesthetized before receiving the scans and that alters brain activity, making brain-behavior data less reliable.
Scientists at the U.S. Department of Energy's Brookhaven National Laboratory, Stony Brook University and their colleagues have created a portable PET scanner for rats, which does not require anesthetic, and which can be worn by the rat during activity. The new device, called RatCAP for Rat Conscious Animal PET, is worn like a collar around the rat's neck during testing, and enables significant movement, according to the researchers. The portable PET scanner only weighs 250 grams.
RatCAP device and brain images: image via nature.com
In one of the tests used to validate the RatCAP, researchers attempted to correlate dopamine levels with behavior, but they got quite a surprising result. The dopamine levels in the brain turned out to be lower, the more active the rat, whereas traditional research models have yielded the opposite results.
"This is perhaps a counterintuitive result because behavioral activation is
typically associated with an increase in dopamine release," said Daniela Schulz,
a Brookhaven behavioral neuroscientist and lead author of the paper. "So our
method provides data which may challenge traditional paradigms and ultimately
improve our understanding of the dopamine system."
"But regardless of the direction, the results clearly demonstrate that RatCAP
can correlate brain function measurements with behavioral measures in a useful
way," she said.
via Physorg; The Brookhaven study is published in the April, 2011 issue of Nature Methods.