Click on image to view larger version.



FIG 5. Maturational decreases of the three diffusion tensor eigenvalues ({lambda}max, {lambda}int, {lambda}min) in the white matter of the splenium of the corpus callosum and the white matter of the posterior limb of the internal capsule for 161 participants of postconceptional ages 7 months to 12 years. Vertical dashed line indicates age of normal term birth: 40 gestational weeks. Dashed line through the {lambda}max data represents an empirical fit to a biexponential function. Solid lines through {lambda}int data (top solid line) and {lambda}min data (bottom solid line) are theoretical predictions for their age-varying values from Monte Carlo simulation of a cylindrical diffusion model, in which the age-dependent parameters , {lambda}max, and SNR are given as input (see Methods for details of the theoretical model).

A, White matter of the splenium of the corpus callosum. Values of {lambda}max (open inverted triangles), {lambda}int (closed circles), and {lambda}min (open squares) are in 10-3 mm2/s.

B, White matter of the splenium of the corpus callosum. Each eigenvalue is expressed in terms of its fraction of the trace of the diffusion tensor Trace(D), where Trace(D) is the sum of the three eigenvalues.

C, White matter of the posterior limb of the internal capsule. Values of {lambda}max (open inverted triangles), {lambda}int (closed circles), and {lambda}min (open squares) are in 10-3 mm2/s.

D, White matter of the posterior limb of the internal capsule. Each eigenvalue is expressed in terms of its fraction of the trace of the diffusion tensor Trace(D), where Trace(D) is the sum of the three eigenvalues.