Poster C91, Sunday, March 25, 1:00-3:00 pm, Exhibit Hall C
Age-related declines in GABA levels in the auditory cortex are associated with neural distinctiveness and auditory perception.
Poortata S. Lalwani1, Holly Gagnon1, Kaitlin Cassady1, Molly Simmonite1, Myria Petrou1, Bradley Foerster1, Rachael Seidler2, Stephan Taylor1, Daniel H. Weissman1, Thad A. Polk1; 1University of Michigan, 2University of Florida
Normal aging is typically associated with decline in perceptual and fluid processing abilities, but preserved crystalized task performance. Previous studies have shown that age-related decline in the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in frontal cortex is correlated with poor cognitive performance (J.BPSC 2016.06.004) . Similarly, studies show that neural patterns in ventral visual cortex in response to different stimulus categories (faces vs. houses) are less distinctive in older adults (PNAS 101:13091) and that lower distinctiveness is associated with poorer performance on fluid processing tasks (Jnl Neurosci 30:9253). Furthermore, application of GABA receptor agonists restores visual neural selectivity in older macaques (Science 300:812). We therefore hypothesized that age-related declines in GABA levels might contribute to reduced neural distinctiveness and associated cognitive declines. Healthy young (ages 18-29) and old adults (over 65) completed a functional Magnetic Resonance Imaging (fMRI) scan in which they listened to foreign speech and music. They also participated in a Magnetic Resonance Spectroscopy (MRS) scan in which GABA levels were estimated in task-activated regions of auditory cortex. Finally, they also complete a battery of cognitive tasks. Data collection is ongoing but preliminary results in 18 young and 17 old subjects suggests that both the distinctiveness of music vs. speech activation patterns and GABA levels decline with age in auditory cortex, that these GABA declines are associated with the decline in neural distinctiveness, and that GABA levels also correlate with performance on an auditory perception task but not on a visual perception task.
Topic Area: PERCEPTION & ACTION: Development & aging