Robert L. Barry1,2, Nellie E. Byun, 2,3,
Jason M. Williams1,2, Michael A. Siuta4, Nicole K.
Speed5,6, Christine Saunders5,6, Aurelio A. Galli,
4,5, Kevin D. Niswender, 4,7, Malcolm J. Avison1,2
1Vanderbilt University Institute of
Imaging Science, Nashville, TN, United States; 2Department of
Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN,
United States; 3Vanderbilt University Institute of Imaging
Science, Nashville, TN, United States; 4Department of Molecular
Physiology and Biophysics, Vanderbilt University, Nashville, TN, United
States; 5Center for Molecular Neuroscience, Vanderbilt University,
Nashville, TN, United States; 6Department of Pharmacology,
Vanderbilt University, Nashville, TN, United States; 7Department
of Medicine, Vanderbilt University, Nashville, TN, United States
Functional
MRI was used to determine the effect of a 14-day high-fat diet on
amphetamine-evoked dopaminergic neurotransmission and functional connectivity
in rats in vivo. High-fat diet blunted
amphetamine-evoked activation in striatal and extrastriatal regions consistent
with reduced dopamine transporter activity due to biochemically confirmed
impaired insulin signaling. Functional
connectivity analysis revealed weakened inter-regional correlations with a
high-fat diet, notably between accumbal-cingulate and striatal-thalamic
regions. These findings link high-fat
diet with impaired dopamine transmission through central insulin resistance
in areas subserving reward, motivation, and habit formation.