Structural asymmetries in motor and language networks in a population of healthy preterm neonates at term equivalent age: A diffusion tensor imaging and probabilistic tractography study

Gender Differences in Language and Motor-Related Fibers in a Population of Healthy Preterm Neonates at Term-Equivalent Age: A Diffusion Tensor and Probabilistic Tractography Study

“…[72][73][74] Another hypothesis is that our results may have been influenced by the effect of prematurity. Indeed, even if the normality of our preterm population was based on robust structural and clinical criteria, as in previous studies, 48,52 we cannot exclude the possibility that the sex related differences observed in the language and motor networks may have been caused by subtle cerebral lesions, because certain studies seem to suggest that preterm males may be more sensitive to brain injuries than females. 75,76 Therefore, it would be of interest to investigate whether these sex differences are also present in healthy term neonates.…”

“…In other published series, differences in tract volumes were not always associated with differences in diffusion indices. 33,48,63,64 Moreover, we used probabilistic tractography, which does not directly rely on diffusion index values, but on the uncertainty orientation of the distribution function, enabling it to progress across regions with principal direction uncertainty and through regions with crossing fibers. Therefore, in probabilistic tractography, volume measurement is not directly linked to diffusion indices.…”

“…For the frontoparietal SLF, a seed mask covered the frontal WM and the waypoint mask covered the frontoparietal WM; for the parieto-temporal SLF, the seed mask was the same as the waypoint mask of the frontoparietal SLF, and the waypoint mask covered the temporal lobe. 48 The TRs were studied separately in 4 subradiations 48 : ATR, the motor and sensory STR, and the PTR. A seed mask was positioned in the bottom of the thalamus and a waypoint mask was positioned in the anterior limb of the internal capsule for the ATR; in the precentral gyrus for the motor STR; in the postcentral gyrus for the sensory STR, and in the occipital lobe for the PTRs.…”

“…51 Finally, the obtained connectivity distributions were thresholded with a probability of 2%. 48,52,53 We calculated the TBV by measuring the volume of the voxels located in the brain mask. 14,54 To assess tract macrostructure, tract volumes and relative tract volumes (defined as the ratio between individual tract volume and TBV) were computed.…”

High‐angular resolution diffusion imaging tractography of cerebellar pathways from newborns to young adults

“…Mean FA, mean ADC, number of streamlines (tract‐count) (e.g., Catani & Thiebaut de Schotten, 2008; Thiebaut de Schotten et al., 2011), mean streamline length (tract‐length) (e.g., Baker et al., 2016; Cohen et al., 2016), and total volume of all streamlines within a tract (tract‐volume) (e.g., Büchel et al., 2004; Eluvathingal, Hasan, Kramer, Fletcher, & Ewing‐Cobbs, 2007; Kulikova et al., 2014; Liu et al., 2010; Takao et al., 2011) corresponding to each cerebellar peduncle pathway (SCP, MCP cog , MCP mot , and ICP) were quantified in each subject. Left and right hemispheric values for each quantity (tract‐count, tract‐volume, mean tract‐length, mean FA, and mean ADC) in each pathway (SCP, MCP cog , MCP mot , and ICP) were compared to check for asymmetry using the Laterality Index (LI) where LI =  (ValueOnLeft – ValueOnRight)/(ValueOnLeft + ValueOnRight).…”