Functional Glutamate and GABA response maps to visual stimulation by functional magnetic resonance spectroscopic imaging

Motivation: Modulations in brain neurotransmitters are crucial in brain function, but have remained accessible only with single voxel MR spectroscopy. Goal(s): We aim to develop a technique to measure functional changes of inhibitory (GABA) and excitatory (Glu) neurotransmitters at high spatio-temporal resolution. Approach: We implemented editing fMRSI, extended by a rosette trajectory readout, an optimized water suppression and crushing schemes, and a reconstruction addressing k-space distortions. Results: We present, for the first time, high resolution maps of GABA and Glu modulated in response to a visual-stimulus, showing increases of GABA in the thalamus and visual cortex, and increases of Glx in the visual cortex. Impact: The proposed fMRSI method offers a novel functional imaging tool for accessing unprecedented metabolic insights underlying brain function in health and diseases.