Mark S. Brown1, Sarah Steinmetz2, Debra Singel3, Susan Hepburn2, Don C. Rojas2
1Radiology, University of Colorado Denver, Aurora, CO, United States; 2Psychiatry, University of Colorado Denver, Aurora, CO, United States; 3Brain Imaging Center, University of Colorado Denver, Aurora, CO, United States
The excitation/inhibition imbalance (EI) theory of the pathophysiology of autism spectrum disorders (ASD) proposes that high ratios of excitatory to inhibitory neuronal processes could explain the ASD phenotype. Evidence for GABAergic inhibitory deficits has been of interest for some time and is supported by a significant body of evidence. We measured levels of GABA in the left auditory cortex using J-edited 1H-MRS in subjects with ASD and compared them to healthy controls. The results show significantly reduced levels of GABA in the ASD group. These results, combined with our previously reported elevated glutamate levels, provide support for the EI theory.