Changes in Functional GABA Levels in Motor Cortex in Older Adults

Research Objectives: To investigate the differences in levels of gamma-aminobutyric acid (GABA) in older adults as assessed by magnetic resonance spectroscopy (MRS) before and after an exercise intervention.

Design: The study is a randomized controlled trial with two intervention arms each lasting 12 weeks. Assessments are done at baseline and follow-up.

Setting: This study involved community dwelling older adults and was performed in a medical center.

Participants: After providing informed consent, we obtained MR spectra of GABA from 9 older adults prior to randomization to one of two exercise programs. The measurements are GABA density and motor skill acquisition.

Interventions: Participants engaged in either an aerobic exercise program or a light strength training intervention each meeting thrice weekly for a period of 12 weeks for 20-45 minutes per session.

Main Outcome Measures: The measurements are MRS evaluated GABA density relative to water across three conditions (rest, entrainment, recall). The behavioral measure was motor skill acquisition in the conditions.

Results: Older participants increased resting levels of GABA after exercise interventions. Within session change in GABA indicates that after exercise intervention, GABA levels increase dynamic range. Increased dynamic range of GABA within-session is associated with more rapid motor skill acquisition and fewer errors.

Conclusions: These data show that an exercise intervention in older adults can increase resting levels of GABA, which is a unique finding. Moreover, the dynamic range may indicate individual differences in how GABA relates to motor skill acquisition in older adults. Additional research is required to confirm these results prior to clinical utility.

Author(s) Disclosures: None.