1. Normalisation des données Oury Monchi, Ph.D. Centre de Recherche, Institut Universitaire de Gériatrie de Montréal & Université de Montréal Centre de Recherche, Institut Universitaire de Gériatrie de Montréal & Université de Montréal

12. Stereotaxic Space based on anatomical landmarks (anterior and posterior commissures) originally used to guide blind stereotaxic neurosurgical procedures (thalamotomy, pallidotomy) now used by NeuroScientific community for interpretation and comparison of results J. Talairach and P. Tournoux, Co-planar stereotactic atlas of the human brain: 3-Dimensional proportional system: an approach to cerebral imaging, Stuttgart, Georg Thieme Verlag, 1988

13. AC-PC line anterior commissure AC-PC line posterior commissure VAC

14. Stereotaxic Space J Talairach & P Tournoux, Co-planar stereotaxic atlas of the human brain, Georg Thieme, 1988

15. Stereotaxic Space

16. Anatomical variability remains Talairach & Tournoux Atlas, 1988 variability of central sulcus from 20 subjects

17. Not Registered Data Images courtesy A. Zijdenbos, MNI

18. Registered Data

19. Registration to Stereotaxic Space facilitates comparisons across – time points – subjects – groups – sites permits averaging between subjects to S/N Allows the use of spatial masks for post-processing (anatomically driven hypothesis testing) allows the use of spatial priors (classification) allows the use of anatomical models (segmentation) provides a framework for statistical analysis with well- established random field models Allows the rapid re-analysis using different criteria Advantages for anatomical/structural imaging:

20. Registration to Stereotaxic Space Provides a conceptual framework for the completely automated, 3D analysis across subjects. Facilitate intra/inter-subject comparisons across –time points, subjects, groups, sites Extrapolate findings to the population as a whole Increase activation signal above that obtained from single subject Increase number of possible degrees of freedom allowed in statistical model Enable reporting of activations as co-ordinates within a known standard space –e.g. the space described by Talairach & Tournoux Advantages for functional imaging:

21. Talairach Atlas is derived from an unrepresentative single 60-yr old female cadaver brain (when most functional activation studies are done on young living subjects!) ignores left-right hemispheric differences has variable slice separation, up to 4mm while it contains transverse, coronal and sagittal slices, it is not contiguous in 3D Drawbacks for functional imaging:

22. Stereotaxic Space Provides a conceptual framework for the completely automated, 3D analysis across subjects. Collins, L., Evans A., et al. have created a replacement target volume for stereotaxic mapping to address weaknesses of the Talairach atlas However, the space and the stereotaxic concept are still worthwhile:

35. Image Registration Registration - i.e. Optimise the parameters that describe a spatial transformation between the source and reference (template) images mritotal: créer la matrice de transformation.xfm Transformation - i.e. Re-sample according to the determined transformation parameters p.ex: mincresample ou resample_tal: appliquer la transformation aux données

60. Idée de Neurolens Pourquoi normaliser des données fonctionnelles sur un ‘template’ anatomique. Création d’un template T2* Visualisation du processus d’optimisation!

61. Slides Aknowledgements Louis Collins, Montreal Neurological Institute Andrew Janke, Montreal Neurological Institute FSL & FreeSurfer Course, fMRIb, Oxford