Activation induced changes in GABA: functional MRS at 7 T with MEGA-sLASER

Chen, Chen; Sigurdsson, Hilmar P.; P�p�s, Sophia E.; Auer, Dorothee P.; Morris, Peter G.; Morgan, Paul S.; Gowland, Penny A.; Jackson, Stephen R.

Abstract

Functional magnetic resonance spectroscopy (fMRS) has been used to assess the dynamic metabolic responses of the brain to a physiological stimulus non-invasively. However, only limited information on the dynamic functional response of γ-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the brain, is available. We aimed to measure the activation-induced changes in GABA unambiguously using a spectral editing method, instead of the conventional direct detection techniques used in previous fMRS studies. The Mescher-Garwood-semi-localised by adiabatic selective refocusing (MEGA-sLASER) sequence was developed at 7 T to obtain the time course of GABA concentration without macromolecular contamination. A significant decrease (−12±5%) in the GABA to total creatine ratio (GABA/tCr) was observed in the motor cortex during a period of 10 minutes of hand-clenching, compared to an initial baseline level (GABA/tCr = 0.11±0.02) at rest. An increase in the Glx (glutamate and glutamine) to tCr ratio was also found, which is in agreement with previous findings. In contrast, no significant changes in NAA/tCr and tCr were detected. With consistent and highly efficient editing performance for GABA detection and the advantage of visually identifying GABA resonances in the spectra, MEGA-sLASER is demonstrated to be an effective method for studying of dynamic changes in GABA at 7 T.

Citation

Chen, C., Sigurdsson, H. P., Pépés, S. E., Auer, D. P., Morris, P. G., Morgan, P. S., …Jackson, S. R. (2017). Activation induced changes in GABA: functional MRS at 7 T with MEGA-sLASER. NeuroImage, 156, 207-213. https://doi.org/10.1016/j.neuroimage.2017.05.044

• Journal Article Type: Article
• Acceptance Date: May 19, 2017
• Online Publication Date: May 19, 2017
• Publication Date: 2017-08
• Deposit Date: May 23, 2017
• Publicly Available Date: May 23, 2017
• Journal: NeuroImage
• Print ISSN: 1053-8119
• Electronic ISSN: 1095-9572
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 156
• Pages: 207-213
• DOI: https://doi.org/10.1016/j.neuroimage.2017.05.044
• Keywords: GABA; MEGA editing; functional MRS; motor cortex; 7T
• Public URL: https://nottingham-repository.worktribe.com/output/875621
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S1053811917304433
• Additional Information: This article is maintained by: Elsevier; Article Title: Activation induced changes in GABA: Functional MRS at 7T with MEGA-sLASER; Journal Title: NeuroImage; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.neuroimage.2017.05.044; Content Type: article; Copyright: © 2017 Elsevier Inc. All rights reserved.