Fig. 2

Diffusion of Mn²⁺ in the rat brain from the 3rd ventricle. a Changes in image intensity of 9 pixels after the intraventricular infusion of 2 mM Mn-bicine (50 μl/h). The distance from the center of the pixel to the 3rd ventricle is shown in the legend for each of the pixels. b The relationship between the T₁ relaxation rate (R _1ob) and image intensity (M _ob). The bold and dotted lines represent, respectively, the regression line of the non-linear fitting and its 95% confidence range of image intensity to an equation: M _ob = M_o*[1 − exp(−TR*·R _1ob)], where M_o* and TR* are apparent values of the equilibrium image intensity and the repetition time of the excitation pulse. Please refer to the text for the details. c Changes in the T₁ relaxation rate of 9 pixels after the intraventricular infusion of Mn-bicine. T₁ relaxation rates were calculated from the image intensity shown in b and the relationship obtained in c. d Fitting data for 7 pixels (195–1367 μm from the 3rd ventricle) to a simple one-dimensional diffusion equation with a single diffusion coefficient. The bold lines show results of fitting to ΔR ₁(x,t) = ΔR ₁₀·erfc[(x − x _off)/(2(D·t)^0.5)], where ΔR ₁₀ = 10.9 ± 0.12 s⁻¹, D = 4.7 × 10⁻⁵ ± 7.3 × 10⁻⁷ mm² s⁻¹, x _off = −1.26 × 10⁻² ± 5.8 × 10⁻⁴ mm (coefficient ± SD)