Team parietal

Overall Objectives
Scientific Foundations
Application Domains
New Results
Contracts and Grants with Industry

Section: New Results

Accurate Definition of Brain Regions Position Through the Functional Landmark Approach

Participants : Bertrand Thirion [Correspondant] , Gaƫl Varoquaux, Jean-Baptiste Poline.

In many application of functional Magnetic Resonance Imaging (fMRI), including clinical or pharmacological studies, the definition of the location of the functional activity between subjects is crucial. While current acquisition and normalization procedures improve the accuracy of the functional signal localization, it is also important to ensure that functional foci detection yields accurate results, and reflects between-subject variability. Here we introduce a fast functional landmark detection procedure, that explicitly models the spatial variability of activation foci in the observed population. We compare this detection approach to standard statistical maps peak extraction procedures: we show that it yields more accurate results on simulations, and more reproducible results on a large cohort of subjects (see Fig 4 ). These results demonstrate that explicit functional landmark modeling approaches are more effective than standard statistical mapping for brain functional focus detection.

Figure 4. (left) Reproducibility index of peak position obtained in the jackknife subsampling procedure for several group analysis techniques. (Right) 2-dimensional example on an axial slice of the scatter of peaks as observed in 3 groups, using the Functional landmark approach (top), and the random effects statistic (bottom). Functional Landmark typically yield more stable results.

For more information, please see [25] .


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