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Background and Purpose: The limbic brain is involved in diverse cognitive,
emotional, and autonomic functions. Injury of the various parts of the
limbic system have been correlated with clinical deficits in MS. The
purpose of this study was to comprehensively examine different regions of
the subcortical limbic system to assess the extent of damage within this
entire system as it may be pertinent in correlating with specific aspects
of cognitive and behavioral dysfunction in MS by using a fully automated,
unbiased segmentation approach. Results: The mean [95% confidence
interval] of the total limbic system volume was lower (0.22% [0.21-0.23])
in MS compared to healthy controls (0.27%, [0.25-0.29], p < .001).
Pairwise comparisons of individual limbic regions between MS and controls
was significant in the nucleus accumbens (0.046%, [0.043-0.050] vs.
0.059%, [0.051-0.066], p = .005), hypothalamus (0.062%, [0.059-0.065]
vs. 0.074%, [0.068-0.081], p = .001), basal forebrain (0.038%,
[0.036-0.040] vs. 0.047%, [0.042-0.051], p = .001), hippocampus (0.47%,
[0.45-0.49] vs. 0.53%, [0.49-0.57], p = .004), and anterior thalamus
(0.077%, [0.072-0.082] vs. 0.093%, [0.084-0.10], p = .001) after
Bonferroni correction. Volume of several limbic regions was significantly
correlated with T2 lesion burden and brain parenchymal fraction (BPF).
Multiple regression model showed minimal influence of BPF on limbic brain
volume and no influence of other demographic and disease state variables.
VBM analysis showed cluster differences in the fornix and anterior
thalamic nuclei at threshold p < 0.05 after adjusting for
covariates but the results were insignificant after family-wise error
corrections. Conclusions: The results show evidence that brain volume
loss is fairly extensive in the limbic brain. Given the significance of
the limbic system in many disease states including MS, such volumetric
analyses can be expanded to studying cognitive and emotional disturbances
in larger clinical trials. FreeSurfer ScLimbic pipeline provided an
efficient and reliable methodology for examining many of the subcortical
structures related to the limbic brain.
119 views reported since publication in 2022.