A new mathematical function to evaluate neuronal morphology using the Sholl analysis.

Area of Science:

• Neuroscience
• Computational Biology
• Morphometrics

Background:

• Sholl analysis visualizes neuronal architecture using concentric circles.
• Existing metrics like Schoenen ramification index (SRI) and neurite bifurcation counts (BN) offer insights into neurite arborization.
• These methods can sometimes fail to differentiate neurons with distinct branching patterns.

Purpose of the Study:

• Introduce a novel mathematical function, the branching index (BI), for quantifying neurite morphology.
• Develop CellTarget software to streamline Sholl analysis and neurite branching quantification.
• Compare the efficacy of BI against SRI and BN in discriminating neuronal morphologies.

Main Methods:

• The branching index (BI) was developed, comparing differences in neurite intersections between concentric circles relative to soma distance.
• CellTarget bioinformatics software was created to automate the extraction of Sholl analysis and neurite branching variables.
• BI, SRI, and BN values were compared using neuronal models and cultured hippocampal neurons.

Main Results:

• The branching index (BI) demonstrated superior ability to discriminate between neurons with varied neurite morphologies compared to SRI and BN.
• Neuronal models and hippocampal cultures treated with dihydrotestosterone showed distinct branching patterns identifiable by BI.
• CellTarget facilitated the quantitative comparison of these different morphometric parameters.

Conclusions:

• The branching index (BI) is a valuable and sensitive parameter for differentiating complex neuronal morphologies.
• The CellTarget software provides a robust platform for advanced neurite morphometric analysis.
• This study enhances the quantitative understanding of neuronal structure and development.