Fig 2. Elementary topological properties for an astrocyte.

A sub-set of measurements obtained in this study are highlighted. The complete list of graphic descriptors of L-Measure is available at http://cng.gmu.edu:8080/Lm/help/index.htm [41]. The primary processes attached to the soma (Stems) are comprised of branches, terminal segments and terminal tips. Branches form the continuous segment between bifurcation points and are made up of one or more cylindrical compartments generated by the NeuronStudio tracing algorithm. The branching order was centrifugal with stems defined as first order. For a specific subtrees, Width and Depth are defined as maximal spread in X and Z perpendicular to the main axis; Height is the radial distance from stem origin to the most distant tip. Upper left inset is the 2D Z projection from ImageJ of the original confocal image, centered on the astrocyte for which the centerline tree is presented to illustrate L-Measure descriptors. Upper right inset is the 2D rendering of the 3D space-filing model of the same astrocyte generated by NeuronStudio.