Altered white matter integrity in individuals with cognitive vulnerability to depression: a tract-based spatial statistics study

Abstract

The microstructure of white matter in patients with major depressive disorder (MDD) has been demonstrated to be abnormal. However, it remains unclear whether these changes exist prior to the onset of disease. In this study, diffusion tensor imaging was used to evaluate white matter integrity in individuals who exhibited cognitive vulnerability to depression (CVD), MDD, and healthy controls (HC). Compared with the HC, MDD exhibited a lower fractional anisotropy (FA) in ten brain regions: the cerebral peduncle, the anterior and posterior limbs of the internal capsule (ALIC and PLIC), the external capsule, the retrolenticular part of the internal capsule (RLIC), the body and splenium of the corpus callosum, the superior and posterior corona radiata, and the cingulum. Moreover, CVD had significantly lower FA in the ALIC, the PLIC, the external capsule, the RLIC, the cerebral peduncle, and the superior corona radiata than did the HC. However, the white matter integrity was not significantly different between the CVD and MDD. These preliminary results indicate that alterations in the white matter observed in CVD may be a marker of vulnerability to MDD and that these alterations may exist prior to the onset of depression.

Early deprivation, atypical brain development, and internalizing symptoms in late childhood

“…Therefore, reduced integrity of the external capsule, as observed in institutionally reared children, may be associated with reduced motivation and behavioral withdrawal, and contribute to higher scores of depression. Our findings are consistent with additional studies showing associations between lower integrity of the external capsule and higher depression symptoms in youth and adult samples (Guo et al, 2012, Bessette et al, 2014, Xiao et al, 2015). …”

Chronic psychosocial stress in mice leads to changes in brain functional connectivity and metabolite levels comparable to human depression

“…This FA increase is suggestive of changes in white matter structure, including fiber rearrangement. The majority of the evidence for white matter changes in depression is actually for decreased FA: this is the case for cingulum, as well as splenium of corpus callosum and external and internal capsules, in adults with (Xiao et al, 2015) and adolescents at risk of (Huang et al, 2011) depression.…”

Exercise protects myelinated fibers of white matter in a rat model of depression

“…Several past preliminary studies found that alterations of the white matter, both in size and morphology, were associated with a diagnosis of depression (Nobuhara et al, ; Nobuhara et al, ; Taylor et al, ) and depression outcomes (Alexopoulos, Kiosses, Choi, Murphy, & Lim, ; Bae et al, ; Taylor et al, ). In fact, the white matter atrophy reported in patients with depression was accompanied by high white matter hyperintensities (WMH) on magnetic resonance imaging (MRI), which most likely represents white matter fiber dysmyelination (Aizenstein et al, ; Dalby et al, ), as well as by low fractional anisotropy (FA) on diffusion tensor imaging (DTI), which most likely represents decreased integrity of myelinated fibers in the white matter (Liu et al, ; Xiao, He, McWhinnie, & Yao, ). Furthermore, lesions of myelinated fibers in the white matter were positively correlated with the severity of depression (Iosifescu et al, ), and subjects with severe damage to myelinated fibers of the white matter had a poor response to antidepressants (Papakostas et al, ; Tham, Woon, Sum, Lee, & Sim, ), indicating that the myelinated fibers of the white matter may not only participate in the pathomechanism of depression but also play an extremely important role in the mechanism of antidepressant therapy.…”

“…Several past preliminary studies found that alterations of the white matter, both in size and morphology, were associated with a diagnosis of depression (Nobuhara et al, 2004;Nobuhara et al, 2006;Taylor et al, 2004) and depression outcomes (Alexopoulos, Kiosses, Choi, Murphy, & Lim, 2002;Bae et al, 2006;Taylor et al, 2004). In fact, the white matter atrophy reported in patients with depression was accompanied by high white matter hyperintensities (WMH) on magnetic resonance imaging (MRI), which most likely represents white matter fiber dysmyelination (Aizenstein et al, 2011;Dalby et al, 2010), as well as by low fractional anisotropy (FA) on diffusion tensor imaging (DTI), which most likely represents decreased integrity of myelinated fibers in the white matter (Liu et al, 2016;Xiao, He, McWhinnie, & Yao, 2015).…”