Diminishing levels of GABA, the primary inhibitory neurotransmitter in the brain, may play a role in cognitive decline as we age, according to a study led by Dr. Ronald Cohen, a professor in the department of clinical and health psychology at the University of Florida College of Public Health and Health Professions and director of the Cognitive Aging and Memory Translational Research Program at UF’s McKnight Brain Institute.
The study, which appeared in the journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, shows an association between higher GABA concentrations in the frontal lobe, a brain region important for complex cognitive functioning, and superior performance on a cognitive test in healthy older adults.
The findings help researchers understand the potential role of age-related GABA decreases in cognitive decline and suggest that declining frontal GABA concentrations may help predict neurodegenerative disease.
“These results are an important step towards personalized approaches to age-related cognitive interventions,” said first author Dr. Eric Porges, a research assistant professor in the PHHP department of clinical and health psychology.
The cause of the relationship remains unknown, and the cognitive assessment used in the study cannot pinpoint which specific cognitive domains, such as attention or memory, might be affected by declining GABA concentrations. However, the relationship suggests a potentially fruitful target for new treatments.
Ninety-four healthy older adults (average age of 73 years) who participated in the study completed the Montreal Cognitive Assessment, which probes several domains of cognition. Dr. Porges and colleagues also measured GABA concentrations in the frontal and posterior cortices of each participant to target regions that are important for high level cognitive functioning.
The analysis supports previously reported GABA reductions during healthy adulthood and revealed that GABA concentrations continue to diminish in both regions into advanced age. The analysis also revealed an association between reduced GABA concentrations in the frontal lobe and poor test scores. This relationship existed even after controlling for age-related changes in cognitive function and tissue atrophy.
“To find that, independent of age and tissue atrophy, GABA levels predict individual differences in cognitive outcome is a provocative finding that may provide insight into physiological mechanisms of age-related cognitive decline,” said Dr. Porges.