Sholl

Purpose

Use Sholl analysis to quantify vessel length, surface area, volume, and diameter in "shells" that represent a specific distance from the marker(s) that you designate as the center point of the analysis. The number of vessel intersections with each shell is also reported.

You can also obtain the numbers of markers and/or puncta that are located within each "shell".

You can rotate the Sholl spheres along with the tracings in 3D by clicking and dragging the mouse.

How it works

Sholl analysis generates a set of nested concentric spheres centered at a selected marker(s). The smallest sphere has a radius of 0. The spheres increase in size by a constant change in radius (r) that you specify. Vesselucida Explorer determines the largest sphere so that it is large enough to enclose everything selected for the analysis.

The center point of the Sholl analysis is the center of the marker or markers that you select for the analysis. If you select more than a single marker, the centroid of the markers is calculated and used as the center point.

What is a centroid?

The centroid is the balance point. Imagine placing a pencil point at the centroid; the cell body tracing would balance on the pencil tip. If the cell body has been traced at several different focal planes, several centroids are calculated. The average of the centroids is the average of each coordinate.

What is a shell?

A shell is the volume contained out to the given radius; it does not include the volume of any smaller shells. This means that the smallest radius row in the results represents a sphere of the given radius.

Procedure

  1. Select the center for the analysis and the structures or markers to be compared:

    1. Select one or more markers that you want to use as the center for the analysis. If you choose more than one marker, the centroid of the markers is calculated and used as the center point.

    2. Select one or more vessels, vessel fragments, puncta, and/or markers to be analyzed in relation to the center point.

  2. Select Sholl Analysis from the Spatial drop-down menu on the Analyze ribbon.

    • Spheres: Choose the starting radius and radius increment for the spheres, as well as line thickness and color.

    • Analyses: Choose the analyses that you want to include.

  3. Click to view result tables.

    The Sholl spheres will also be displayed in the main Vesselucida Explorer window.

    • To hide the Sholl spheres, click Remove analysis graphics on the Analyze or View ribbon.

Analysis results

Vessels report

Radius: Each radius corresponds to a shell. The number shown is the position of the shell in µm from the designated center point.

Intersections: Number of intersections between vessel and sphere at the given radius.

Length: Total length in µm of all vessels passing through a shell.

SArea: Total surface area in µm2 of all vessels passing through a shell.

Volume: Total volume in µm3 of all vessels passing through a shell.

Avg. Diameter: Average Diameter in µm of all vessels passing through a shell.

Markers report

Displays the number of markers in each shell for each marker type.

Puncta report

Displays the number of puncta, the average surface area, and the average volume of the puncta in each shell.

 

References

Sholl, D. A. (1953). Dendritic organization in the neurons of the visual and motor cortices of the cat. J. Anat. 87, 387-406.

Rodger J., Drummond E.S., Hellström M., Robertson D., Harvey A.R .(2012). Long-Term Gene Therapy Causes Transgene-Specific Changes in the Morphology of Regenerating Retinal Ganglion Cells. PLoS ONE 7(2): e31061. doi:10.1371/journal.pone.0031061