Very large fMRI study using the IMAGEN database: sensitivity - speci?city and population effect modelling in relation to the underlying anatomy
Item Type:Journal Article
Citation:Thyreau, B., Schwartz, Y., Thirion, B., Frouin, V., Loth, E., Vollstadt-Klein, S., Paus, T., Artiges, E., Conrod, P. J., Schumann, G., Whelan, R., Poline, J., Very large fMRI study using the IMAGEN database: sensitivity - speci?city and population e?ect modelling in relation to the underlying anatomy, NeuroImage (2012)
Very large fMRI study using the IMAGEN database- sensitivity - specificity and population effect modelling in relation to the underlying anatomy.pdf (Accepted for publication (author's copy) - Peer Reviewed) 1.169Mb
In this paper we investigate the use of classical fMRI Random Effect (RFX) group statistics when analysing a very large cohort and the possible improvement brought from anatomical information. Using 1326 subjects from the IMAGEN study, we first give a global picture of the evolution of the group effect t-value from a simple face-watching contrast with increasing cohort size. We obtain a wide activated" pattern, far from being limited to the reasonably expected brain areas, illustrating the difference between statistical significance and practical significance. This motivates us to inject tissue-probability information into the group estimation, we model the BOLD contrast using a matter-weighted mixture of Gaussians and compare it to the common, single-Gaussian model. In both cases, the models parameters are estimated per-voxel for one subgroup, and the likelihood of both models is computed on a second, separate subgroup to reflect models generalization capacity. Various group sizes are tested, and significance is asserted using a 10-fold cross-validation scheme. We conclude that adding matter information consistently improves the quantitative analysis of BOLD responses in some areas of the brain, particularly those where accurate inter-subject registration remains challenging.
Author: WHELAN, ROBERT
Type of material:Journal Article
Availability:Full text available