Zoom-in around the NaD absorption line for the spectra of four galaxies at different distances from the center (in black). Colored lines are MILES SSP models with fixed age, metallicity, [α/Fe], and IMF, and color-coded by [Na/Fe] (red solar and blue 0.6, as highlighted by the color bar at the top). The upper panel shows the Voronoi bin corresponding to the central dust lane (0001). There, the contribution to the NaD line is not only stellar but also comes from the cold gas. A minimal contribution can also be seen in the second panel (Spec 0004), but in all other bins shown, in which the dust lane is not present, the contribution is stellar with a super-solar [Na/Fe] abundance value.