GABA: a new imaging biomarker of neurodegeneration in multiple sclerosis?

This scientific commentary refers to ‘Reduced gamma-aminobutyric acid concentration is associated with physical disability in progressive multiple sclerosis’, by Cawley et al. (doi:10.1093/brain/awv209). Conventional MRI has improved the diagnostic work-up and monitoring of many chronic neurological disorders, thanks to its ability to detect brain abnormalities with great sensitivity. One important limitation of conventional MRI, however, is its lack of specificity with regard to different pathological substrates underlying disease. A number of recently developed MRI techniques have shown the ability to complement conventional MRI by enhancing specificity to pathological changes. However, the ultimate goal of obtaining imaging biomarkers that closely reflect specific pathological features (such as progressive neuroaxonal damage/injury leading to neurodegeneration) and mechanisms (e.g. mitochondrial dysfunction, microglial activation, iron deposition) has yet to be achieved.Among the various advanced MRI techniques, proton magnetic resonance spectroscopy (1H-MRS) is unique in its ability to characterize the chemical pathology of brain tissue (Barker et al. , 2010). By applying this technique both …