Resolution:
standard / ## Figure 1.
Illustration of the processing steps from raw data to the final brain map result. After pre-processing (bias correction, segmentation, normalization, modulation and
smoothing), confidence intervals (CI) were obtained for each voxel of the brain. This
allowed to construct a 'typical brain', i.e. a 5D matrix with 3 spatial dimensions,
1 dimension for the low and high bounds of the CI and the last dimension for number
of CI). In this study, 5 CI were built after 3000, 3500, 4000, 4500 and 5000 bootstrap
resamples. The 'typical brain' was therefore of dimensions 91*109*91*2*5 (91 voxels
in x, 109 in y, 91 in z, 2 for upper/lower bound/5 for the 5 CI). Each voxel of each
dyslexic subject was then classified as within or outside the 5 CIs. Results were
then averaged, resulting in a percentage map of difference (PMD). A random attribution
of scans to the control and dyslexic groups was used to compute the probability to
find the observed values under H0, the null hypothesis according to which dyslexics
and controls were sampled by chance from the same population.
Pernet |