> For the complete documentation index, see [llms.txt](https://bridge-lab.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bridge-lab.gitbook.io/docs/imaging/image-analysis/registration/tbss.md).

# TBSS

Tract-Based Spatial Statistics is a tool that uses FA maps to generate an FA skeleton. TBSS takes all FA maps for each subject in a dataset, registers those maps together, and generates a mean FA WM skeleton.

<figure><img src="https://2091072347-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FiDgWwNd2W0ZWe2XnzLuq%2Fuploads%2FATCA7WQJkk2hR134CKec%2FSteps-of-original-FSL-TBSS-Pipeline-with-example-images.jpg?alt=media&amp;token=e34f09a3-028b-495d-8ad7-e3bb867965c2" alt=""><figcaption></figcaption></figure>

[TBSS has a robust user guide that can help users through a variety of uses](https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/TBSS).

<figure><img src="https://2091072347-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FiDgWwNd2W0ZWe2XnzLuq%2Fuploads%2FUBcQLq3DUWYtkEz1JRDQ%2Feg_skel_all_FA.png?alt=media&amp;token=1fdc1e76-2ffc-4f0c-9c0b-ac6030d52c2c" alt=""><figcaption></figcaption></figure>