Metabolic response in deactivated areas using fMRS at 3T

Motivation: Functional Magnetic Resonance Spectroscopy allows quantifying dynamic changes in metabolite concentration within activated brain areas. Comparatively less is known about metabolic dynamics in areas of Negative BOLD Response (NBR). Goal(s): This study's purpose is to explore the metabolic response in deactivated areas within the occipital lobe. Approach: A block-designed visual stimulus tailored to induce NBR in V1 was administered to 17 heathy volunteers. Data were acquired at 3T with a semiLASER sequence. A functional localizer was used to place the MRS VOI within NBR area. Results: Results showed a significant deactivation around the calcarine sulcus (-0.49%±0.47%). Significant glutamate and lactate decreases were observed. Impact: Neurometabolic profiling during deactivation can help elucidating the neural origin of NBR, offering information about brain metabolic diseases through assessment of dissociation between neurovascular and neurometabolic coupling. Lactate and glutamate decreases are coherent with reduced excitation within the deactivated area.