Mapping Brain Metabolic Connectivity in Awake Rats with PET and Optogenetic Stimulation

Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland 20852, Behavioral Neuropharmacology and Neuroimaging Laboratory, Medical Department, Brookhaven National Laboratory, Upton, New York 11973, Department of Psychology, Stony Brook University, Stony Brook New York 11794, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, and Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029.
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience (Impact Factor: 6.34). 04/2013; 33(15):6343-6349. DOI: 10.1523/JNEUROSCI.4997-12.2013
Source: PubMed


Positron emission tomography (PET) with [(18)F]2-fluoro-2-deoxy-d-glucose was used to measure changes in regional brain glucose metabolism (BGluM) in response to optogenetic stimulation (using the excitatory channelrhodopsin-2) of the nucleus accumbens (NAc) in awake rats. We demonstrated not only increases in BGluM that correlated with c-Fos expression in the region of stimulation, but also BGluM increases in the ipsilateral striatum, periaqueductal gray, and somatosensory cortex, and in contralateral amygdala, ventral pallidum, globus pallidus, and hippocampus, as well as decreases in BGluM in regions of the default mode network (retrosplenial cortex and cingulate gyrus) and secondary motor cortex. Additional exploration of c-Fos expression in regions found to be activated by PET results found corroborating evidence, with increased c-Fos expression in the ipsilateral somatosensory cortex, contralateral amygdala and globus pallidus, and bilateral periaqueductal gray. These findings are consistent with optogenetic excitation of the area of stimulation (NAc), as well as with stimulatory and inhibitory effects on downstream regions. They also confirm the utility of PET imaging to monitor connectivity in the awake rodent brain.

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