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, SUPPLEMENTAL DATA Supplemental data Figure 1: Point spread function of the different 23 Na MRI acquisitions Point spread functions (PSF) of a) one set of data (240 spokes acquired using golden angle approach, temporal resolution 30s) with aPSFFWHM of 2.24 points corresponding to 7.84mm, b) the weighted 23 Na MRI acquisition used for 23 Na fMRI (weighted 10080 spokes, temporal resolution 30s) with a PSFFWHM of 1.81 points corresponding to 6.34mm and c) the whole k-­-space sampling (10080 spokes, temporal resolution 20min10s2: Signal variations during the right hand motor task in a) the supplementary motor area

, Supplemental Figure 6: TE dependencies of 23 Na MR signal decays for total, mobile and restricted pools of sodium in gray matter during basal period, excitation and inhibition and potential related phenomenons occurring within the neuro-glial-vascular ensemble

. Adapted-from-chatton, These phenomenons may induce as shown in c) increase of 23 Na signal at TE 1 =0.2ms in relation with increase in CBV, and decrease in 23 Na signals at TE 2 and TE 3 relative to the decrease in 23 Na signals of the mobile pools. d) Schematic representation of the neuro-glial-vascular ensemble following deactivation with Na eflux and decrease CBV that may induce e) decrease in 23 Na signal at TE 1 , and increase in 23 Na signals at TE 2 and TE 3 in the inhibited area, Schematic representation of the neuro-glial-vascular ensemble during the resting period, vol.17, 2016.

, T 2 *(Na mobile-Inhibition )=31ms, T 2 * (Na restricted-Inhibition )=5ms. The green curves represented the functional 23 Na contrasts, 0%)