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closeWhy handedness correlates with depth of central sulcus instead of diffusion MRI indices, such as FA or MD?
Posted by lilongchuan on 27 Sep 2010 at 00:13 GMT
It is interesting to see that in this study, the authors could correlate handedness with central sulcus depth but not with FA, an important diffusion MRI index in chimpanzees. When reading the existing literature regarding the correlations between handedness and brain asymmetry, either in humans or in chimpanzees, it is interesting to see that the studies in correlating central sulcus depth and handedness seem to be more consistent compared to those correlating handedness and FA. This might be explained by the fact that diffusion MRI is a relatively more complicated technique compared to structural MRI. A large number of parameters need to be carefully chosen to generate a set of reliable data, ranging from diffusion gradient directions & strength, choice of b-values, removal of susceptibility distortion, limited voxel resolution (therefore partial voluming), choice of tractography algorithm, etc.. All these could influence the final outcomes in diffusion MRI, resulting in relatively discrepant conclusions in those diffusion MRI studies.
Moreover, FA is a scalar based on diffusion tensor model (simplified description of water diffusion process) and has limitations itself. For example, in areas where complex fiber trajectories exist (crossing, kissing, branching fibers), which should be the case in majority number of voxels in diffusion MRI data, it might not be able to accurately reflect the white-matter tract properties. Therefore, it would be interesting to see if handedness will be correlated with some other indexes that are supposedly more accurate than FA in the future.