GABA Levels Are Significantly Reduced in the Visual, Motor, and Auditory Cortex of Patients with Mild Cognitive...

Area of Science:

• Neuroscience
• Neuroimaging
• Biochemistry

Background:

• Mild cognitive impairment (MCI) is associated with potential neurochemical changes.
• Gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter, has been implicated in cognitive function.
• Previous research on GABA levels in patients with mild cognitive impairment (pwMCI) has yielded inconsistent findings.

Purpose of the Study:

• To investigate GABA+ levels in multiple brain regions of pwMCI compared to healthy controls.
• To assess the impact of different reference molecules (creatine and water) and tissue composition correction on GABA+ quantification.
• To determine if GABA+ reductions are widespread in pwMCI.

Main Methods:

• Utilized magnetic resonance spectroscopy (MRS) to quantify GABA+ levels.
• Studied 37 pwMCI and 163 healthy controls across six brain regions.
• Employed creatine and water as reference molecules and analyzed tissue composition correction.

Main Results:

• GABA+ levels, when referenced to water, were significantly lower in pwMCI across all six regions, even after tissue correction.
• When referenced to creatine, most regions showed reduced GABA+ in pwMCI, even after controlling for tissue composition.
• These findings indicate a widespread reduction of GABA+ in pwMCI.

Conclusions:

• pwMCI exhibit reduced GABA+ levels throughout the brain.
• These reductions extend to brain regions not typically considered primary sites of cognitive impairment.
• GABA+ deficits may be a significant factor contributing to functional deterioration in pwMCI.