Title
Extrapolation of sparse tensor fields: application to the modeling of brain variability.
Abstract
Modeling the variability of brain structures is a fundamental problem in the neurosciences. In this paper, we start from a dataset of precisely delineated anatomical structures in the cerebral cortex: a set of 72 sulcal lines in each of 98 healthy human subjects. We propose an original method to compute the average sulcal curves, which constitute the mean anatomy in this context. The second order moment of the sulcal distribution is modeled as a sparse field of covariance tensors (symmetric, positive definite matrices). To extrapolate this information to the full brain, one has to overcome the limitations of the standard Euclidean matrix calculus. We propose an affine-invariant Riemannian framework to perform computations with tensors. In particular, we generalize radial basis function (RBF) interpolation and harmonic diffusion PDEs to tensor fields. As a result, we obtain a dense 3D variability map which proves to be in accordance with previously published results on smaller samples subjects. Moreover, leave one (sulcus) out tests show that our model is globally able to recover the missing information when there is a consistent neighboring variability. Last but not least, we propose innovative methods to analyze the asymmetry of brain variability. As expected, the greatest asymmetries are found in regions that includes the primary language areas. Interestingly, such an asymmetry in anatomical variance could explain why there may be greater power to detect group activation in one hemisphere than the other in fMRI studies.
Year
DOI
Venue
2005
10.1007/11505730_3
IPMI
Keywords
Field
DocType
sparse tensor field,anatomical variance,consistentneighboring variability,full brain,anatomical structure,average sulcal curve,variability map,sulcal distribution,brain variability,brain structure,sulcal line,second order,tensors,riemannian geometry
Matrix calculus,Pattern recognition,Tensor,Matrix (mathematics),Interpolation,Tensor field,Extrapolation,Artificial intelligence,Tensor calculus,Mathematics,Covariance
Conference
Volume
ISSN
ISBN
19
1011-2499
3-540-26545-7
Citations 
PageRank 
References 
18
3.96
8
Authors
5
Name
Order
Citations
PageRank
P Fillard1123875.70
Vincent Arsigny273350.69
Xavier Pennec35021357.08
Paul Thompson43860321.32
Nicholas Ayache5108041654.36