Tractography reveals a profound alteration in the structural integrity of the ILF and the IFOF in individuals with congenital prosopagnosia compared with their matched controls. Further analyses confirmed a reduction in the microstructural integrity of white matter along the trajectory of the ILF and IFOF in both hemispheres. (a,b) Axial slices showing the bilateral ILF and the IFOF in individuals with congenital prosopagnosia and their matched controls. The gender and age of each individual with congenital prosopagnosia and their matched control is indicated below each slice. (c,d) The whole-brain voxel-wise fractional anisotropy analysis revealed a reduction in fractional anisotropy (c) in four regions along the trajectory (d) of the ILF (blue) and IFOF (yellow) in the congenital prosopagnosia group. Montreal Neurological Institute (MNI) coordinates and the number of voxels are provided below each image. All images are displayed in neurological convention.

The relation between alterations in structural connectivity in ventral occipito-temporal cortex and poor face-recognition ability. (a) The congenital prosopagnosia group showed a reduction in the microstructural integrity of the bilateral ILF and IFOF, but not in the two callosal tracts. LH, left hemisphere; RH, right hemisphere. (b) A reduction in the percentage of fibers in the right IFOF was associated with an increase in errors in face recognition. (c,d) Similarly, a reduction in the mean fractional anisotropy (c) and percentage of voxels (d) in the right ILF were also associated with an increase in errors in face recognition. Error bars indicate s.e.m.