Poster D71, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
Asymmetric associations between GABA and intrinsic auditory network activity
Samika Kumar1, Srikantan Nagarajan1, Fumiko Hoeft1, Roeland Hancock1; 1University of California, San Francisco
Gamma-aminobutyric acid (GABA) regulates excitation-inhibition balance critical for sustaining local cortical oscillations, particularly in the gamma (>40 Hz) range, and long-range oscillatory synchrony between regions, which are reflected in resting-state functional connectivity (RSFC). The resting-state auditory network reflects asymmetries in connectivity that may reflect the asymmetric specialization of auditory regions in processing high- and low-frequency components of the speech signal. This study examined how GABA, measured using magnetic resonance spectroscopy (MRS), moderates RSFC within the auditory network. GABA was measured bilaterally from voxels in the superior temporal gyri (STG) in 18 healthy adults. Seed-to-voxel RSFC was calculated from bilateral seeds in the primary auditory cortex and planum temporale. GABA in the left STG was associated with decreased RSFC between left hemisphere ROIs and the left precentral gyrus and premotor cortex, as well as the right STG. Right hemisphere GABA was positively correlated with RSFC between left auditory cortex ROIs and the right prefrontal cortex and negatively correlated with RSFC between left auditory cortex ROIs and the left PFC, as well as right language regions. As hypothesized, left hemisphere GABA seems to more strongly modulate RSFC in temporal and language-related regions. However, right hemisphere GABA reveals a more complex relationship with RSFC extending beyond the language network, and it may be shown to contribute to the atypical language network, in abnormally increased strength, with further investigation.
Topic Area: LANGUAGE: Other