GABA decrease is associated with degraded neural specificity in the visual cortex of glaucoma patients

Abstract

Glaucoma is an age-related neurodegenerative disease of the visual system, affecting both the eye and the brain. Yet its underlying metabolic mechanisms and neurobehavioral relevance remain largely unclear. Here, using proton magnetic resonance spectroscopy and functional magnetic resonance imaging, we investigated the GABAergic and glutamatergic systems in the visual cortex of glaucoma patients, as well as neural specificity, which is shaped by GABA and glutamate signals and underlies efficient sensory and cognitive functions. Our study showed that among the older adults, both GABA and glutamate levels decrease with increasing glaucoma severity regardless of age. Further, the reduction of GABA but not glutamate predicted the neural specificity. This association was independent of the impairments on the retina structure and age. Our results suggest that glaucoma-specific decline of GABA undermines neural specificity in the visual cortex and that targeting GABA could improve the neural specificity in glaucoma.

Glaucoma Rehabilitation using ElectricAI Transcranial Stimulation (GREAT) – Study Protocol for Randomized Controlled Trial using Combined Perceptual Learning and Transcranial Electrical Stimulation for Vision Enhancement

“…Previous research has demonstrated the role of (gamma-aminobutyric acid) GABA+ in inhibitory control, while glutamate/glutamine (Glx) primarily affects excitatory control, thereby contributing to the balance between inhibition and excitation (known as the I-E balance). A recent study showed that both GABA and glutamate level was associated with glaucoma severity and targeting GABA could possibly enhance the neural speci city in visual cortex [57]. To obtain accurate metabolic concentrations, the MEGA-PRESS sequence will be used to calculate GABA+ values, and the PRESS sequence will be used to measure Glx levels.…”