Analysis of Brain Activation Patterns Using a 3-D Scale-Space Primal Sketch

Tony Lindeberg, Pär Lidberg and Per E. Roland

Technical report ISRN KTH NA/P--98/18--SE. Department of Numerical Analysis and Computing Science, KTH (Royal Institute of Technology), S-100 44 Stockholm, Sweden, September 1998.

Revised version in Human Brain Mapping, vol 7, no 3, pp 166--194, 1999.

Earlier version presented in Proc. 3rd International Conference on Functional Mapping of the Human Brain Mapping, Copenhagen, Denmark, May 19--23, 1997. Neuroimage, Vol.~5, No.~4, p.~393, 1997.


A fundamental problem in brain imaging concerns how to define functional areas consisting of neurons which are activated together as populations. We propose that this issue can be ideally addressed by a computer vision tool referred to as the scale-space primal sketch. This concept has the attractive properties that it allows for automatic and simultaneous extraction of the spatial extent and the significance of regions with locally high activity. In addition, a hierarchical nested tree structure of activated regions and subregions is obtained.

The subject in this article is to show how the scale-space primal sketch can be used for automatic determination of the spatial extent and the significance of rCBF changes. Experiments show the result of applying this approach to functional PET data, including a preliminary comparison with two more traditional clustering techniques. Compared to previous approaches, the method overcomes the limitations of performing the analysis at a single scale or assuming specific models of the data.

Keywords: brain activation, human brain mapping, functional region, scale-space, primal sketch, scale selection, blob detection, multi-scale representation, computer vision

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Background and related material: (General reference on the scale-space primal sketch) (Monograph on scale-space theory)