Fsl 4.1.0 has been released and is now ready for download, new features include:

• FNIRT - FMRIB's Nonlinear Image Registration Tool. The first release of an accurate and yet fast nonlinear registration tool. This replaces IRTK, and is based on a similar warp field representation, but a) includes relative bias field modelling for improved accuracy and b) is very fast because of explicit computation of the cost function Hessian. FEAT, MELODIC, TBSS and FSL-VBM have all been updated to use FNIRT.
• FEAT v5.98. Various improvements, including FNIRT nonlinear registration, outlier modelling in higher-level analysis and higher-level voxelwise covariates (e.g., for structural confound modelling). A new script feat_gm_prepare makes it easy to process structural data for use as a higher-level voxelwise confound covariate.
• randomise v2.1. Various improvements, including improved handling of confounds, TFCE optimisation for TBSS and parallelisation over multiple computers.
• FAST v4.1 is now the default tissue-type segmentation program, and FAST v3 has been removed from FSL. Hence all programs including SIENA/SIENAX now use FAST v4.
• FIRST subcortical segmentation is now considerably faster, has improved boundary correction and now includes a cerebellum model.
• The outputting of ANALYZE files is no longer supported as the format is now strongly discouraged.

The binaries, sources and test data can be downloaded from:

http://www.fmrib.ox.ac.uk/fsldownloads/

Matthew