Cortical Neurotransmitters Measured by Magnetic Resonance Spectroscopy Change Following Traumatic Brachial Plexus
Ryckie G Wade1,2, Gráinne Bourke1,2, Alexandra M Olaru3
1Department of Plastic and Reconstructive Surgery, Leeds Teaching Hospitals Trust, Leeds, United Kingdom.
Journal of Brachial Plexus and Peripheral Nerve Injury
|January 30, 2025
Summary
Traumatic brachial plexus injuries initially alter brain GABA levels, with lower ratios in the affected hemisphere. These differences normalize over time, suggesting GABA as a potential therapeutic target for recovery.
Area of Science:
- Neuroscience
- Neuroimaging
- Biochemistry
Background:
- Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain.
- GABA plays a role in cortical plasticity and functional recovery following central nervous system injury.
- The impact of traumatic brachial plexus injuries (tBPIs) on brain GABA levels remains largely uncharacterized.
Purpose of the Study:
- To investigate changes in brain GABA concentrations in individuals following tBPIs.
- To explore GABA's role in cortical plasticity and potential as a pharmacological target for functional recovery after tBPIs.
Main Methods:
- Serial magnetic resonance imaging (MRI) including T1-weighted and J-edited spectroscopy (MEGA-PRESS) was performed on seven males post-tBPI.
- Quantification of GABA, creatine (Cr), and N-acetylaspartate (NAA) concentrations was conducted using jMRUI software.
- Interhemispheric metabolite ratios (GABA:NAA, GABA:Cr, NAA:Cr) and tissue proportions were analyzed.
Main Results:
- Within weeks of injury, the hemisphere ipsilateral to the injured limb showed significantly reduced GABA:NAA and GABA:Cr ratios compared to the contralateral side.
- No interhemispheric differences were observed in the NAA:Cr ratio.
- By 12 months post-injury, interhemispheric differences in metabolite concentrations normalized, with no changes in gray matter, white matter, or CSF proportions.
Conclusions:
- Traumatic brachial plexus injuries induce temporary interhemispheric alterations in GABA concentrations within the sensory and motor cortex.
- These GABA level changes represent a potential, yet unconfirmed, pharmacological target for enhancing functional recovery.
- Further research is warranted to validate these findings and explore therapeutic interventions targeting GABA pathways.
