Positron emission tomography (PET) neuroimaging and behavioral assays in rodents are widely used in neuroscience. PET gives insights into the molecular processes of neuronal communication, and behavioral methods analyze the actions that are associated with such processes. These methods have not been directly integrated, because PET studies in animals have until now required general anesthesia to immobilize the subject, which precludes behavioral studies. We present a method for imaging awake, behaving rats with PET that allows the simultaneous study of behavior. Key components include the 'rat conscious animal PET' or RatCAP, a miniature portable PET scanner that is mounted on the rat's head, a mobility system that allows considerable freedom of movement, radiotracer administration techniques and methods for quantifying behavior and correlating the two data sets. The simultaneity of the PET and behavioral data provides a multidimensional tool for studying the functions of different brain regions and their molecular constituents.
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We thank W. Lenz for mechanical design and fabrication; D. Alexoff for assistance with rat handling; S. Park for coincidence-processing methods; W. Schiffer for assistance with data analysis; C. Reiszel for expertise in catheter design; V. Radeka, R. Lecomte and R. Fontaine for contributions to the electronics; J. Logan for advice on kinetic modeling; J. Fowler and the personnel of the Brookhaven National Laboratory PET center and cyclotron for making the radiotracers available for our studies and N. Volkow for proposing the idea of a conscious-animal PET scanner. The research was carried out at Brookhaven National Laboratory under contract number DE-AC02-98CH10886 with the US Department of Energy and funded by the Department of Energy's Office of Biological and Environmental Research.
The authors declare no competing financial interests.
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Schulz, D., Southekal, S., Junnarkar, S. et al. Simultaneous assessment of rodent behavior and neurochemistry using a miniature positron emission tomograph. Nat Methods 8, 347–352 (2011). https://doi.org/10.1038/nmeth.1582
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