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Age-related GABA- and glutamatergic differences in SMA during bimanual coordination
Joana Frieske1,2,3, Sara Magalhães Ferreira1, Shanti Van Malderen1,2,3
1Neuroplasticity and Movement Control Research Group, Rehabilitation Research Institute (REVAL), Hasselt University, Diepenbeek, Belgium.
Imaging Neuroscience (Cambridge, Mass.)
|December 1, 2025
Summary
Older adults show lower brain metabolites like GABA+ and Glx in the Supplementary Motor Area (SMA). A lower inhibitory-excitatory balance (GABA+/Glx ratio) during tasks predicts better bimanual coordination in older individuals.
Area of Science:
- Neuroscience
- Motor Control
- Aging Research
Background:
- The Supplementary Motor Area (SMA) is crucial for bimanual coordination and complex motor control.
- Understanding age-related changes in SMA neurometabolites (GABA+ and Glx) and their impact on motor performance is limited.
- Neurometabolite alterations may underlie age-related declines in motor function.
Purpose of the Study:
- To investigate age-related differences in gamma-aminobutyric acid (GABA+) and glutamate + glutamine (Glx) levels within the SMA.
- To examine the relationship between these neurometabolites and bimanual motor performance across the adult lifespan.
- To explore task-related modulations of neurometabolites during a bimanual coordination task.
Main Methods:
- Magnetic Resonance Spectroscopy (MRS) was used to measure neurometabolite concentrations in the SMA.
- Participants included young adults and older adults performing a Bimanual Tracking Task (BTT).
- Neurometabolite levels were assessed during rest and task conditions.
Main Results:
- Younger adults outperformed older adults on the Bimanual Tracking Task.
- Older adults exhibited lower SMA GABA+ and Glx levels compared to young adults.
- No significant age-related differences were found in the GABA+/Glx ratio; task performance did not significantly alter metabolite levels.
- A lower GABA+/Glx ratio during the task was associated with better bimanual performance in older adults.
Conclusions:
- Neurometabolite concentrations in the SMA decrease with age, but the overall inhibitory-excitatory balance may be maintained.
- Task-specific neurometabolite changes were not observed.
- Reduced inhibitory tone (lower GABA+/Glx ratio) during motor tasks may be beneficial for bimanual coordination in older adults.

