Activation induced changes in GABA: Functional MRS at 7T with MEGA-sLASER.
Chen Chen1, Hilmar P Sigurdsson2, Sophia E Pépés2
1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom.
Neuroimage
|May 24, 2017
Summary
Functional magnetic resonance spectroscopy (fMRS) using MEGA-sLASER revealed a decrease in brain gamma-aminobutyric acid (GABA) during hand-clenching. This non-invasive technique offers new insights into inhibitory neurotransmitter dynamics.
Area of Science:
- Neuroscience
- Metabolic Imaging
- Neurochemistry
Background:
- Functional magnetic resonance spectroscopy (fMRS) non-invasively assesses brain metabolic dynamics.
- Limited data exists on the dynamic functional response of gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter.
Purpose of the Study:
- To unambiguously measure activation-induced changes in brain GABA levels.
- To utilize a spectral editing method for enhanced GABA detection.
Main Methods:
- Development of the Mescher-Garwood-semi-localised by adiabatic selective refocusing (MEGA-sLASER) sequence at 7 Tesla.
- Acquisition of time-course GABA concentration data, minimizing macromolecular contamination.
- Non-invasive monitoring of metabolic responses to a physiological stimulus (hand-clenching).
Main Results:
- A significant decrease (-12±5%) in the GABA to total creatine ratio (GABA/tCr) was observed in the motor cortex during hand-clenching.
- An increase in the Glx (glutamate and glutamine) to tCr ratio was detected, consistent with prior research.
- No significant changes in N-acetylaspartate (NAA)/tCr or tCr levels were found.
Conclusions:
- The MEGA-sLASER sequence demonstrates effective and consistent GABA detection at 7T.
- This method allows for the study of dynamic changes in GABA, offering advantages in visual identification of GABA resonances.
- The findings provide valuable insights into the dynamic regulation of inhibitory neurotransmission in the human brain.
