GABA Levels are Significantly Lower in Mild Cognitive Impairment Patients

Poster Session C - Sunday, April 14, 2024, 5:00 – 7:00 pm EDT, Sheraton Hall ABC

Mark Zuppichini¹ (markzupp@umich.edu), Abbey Hamlin², Quan Zhou¹, Esther Kim¹, Kayla Wyatt¹, Noah Reardon¹, Thad Polk¹; ¹University of Michigan, ²University of Texas at Austin

Gamma-aminobutyric acid (GABA), the brain’s major inhibitory neurotransmitter, has been identified as one factor that might contribute to the functional deterioration and cognitive decline observed in Alzheimer’s disease (AD). Animal models of AD have established an important role for GABA and human functional neuroimaging studies have observed hyperexcitability in brain regions associated with cognitive and sensory function in both AD patients and in patients with mild cognitive impairment (MCI), consistent with a disruption of inhibitory GABAergic processing. Furthermore, studies utilizing magnetic resonance spectroscopy (MRS) have observed age-related reductions in GABA in several brain regions in healthy older adults. However, there has yet to be an MRS study comparing GABA levels in MCI patients compared to age-matched healthy older adults. In the present study, we utilized MRS to measure GABA levels in bilateral auditory, sensorimotor, and ventrovisual voxels of interest (VOI) in healthy older adults (n=30) and MCI patients (n=17). Additionally, we applied a tissue correction strategy to control for the dependency of GABA measurements on underlying VOI tissue composition. MCI patients exhibited significantly (p < .001) lower levels of GABA in all VOIs except for the left auditory VOI (MCI still exhibited lower levels in this region, but the effect was not significant).

Topic Area: METHODS: Neuroimaging