Increased white matter connectivity in euthymic bipolar patients: diffusion tensor tractography between the subgenual cingulate and the amygdalo-hippocampal complex

To determine whether white matter network disruption mediates the association between MRI markers of cerebrovascular disease (CeVD) and cognitive impairment. Participants (n = 253, aged ≥60 years) from the Epidemiology of Dementia in Singapore study underwent neuropsychological assessments and MRI. CeVD markers were defined as lacunes, white matter hyperintensities (WMH), microbleeds, cortical microinfarcts, cortical infarcts and intracranial stenosis (ICS). White matter microstructure damage was measured as fractional anisotropy and mean diffusivity by tract based spatial statistics from diffusion tensor imaging. Cognitive function was summarized as domain-specific Z-scores. Lacunar counts, WMH volume and ICS were associated with worse performance in executive function, attention, language, verbal and visual memory. These three CeVD markers were also associated with white matter microstructural damage in the projection, commissural, association, and limbic fibers. Path analyses showed that lacunar counts, higher WMH volume and ICS were associated with executive and verbal memory impairment via white matter disruption in commissural fibers whereas impairment in the attention, visual memory and language were mediated through projection fibers. Our study shows that the abnormalities in white matter connectivity may underlie the relationship between CeVD and cognition. Further longitudinal studies are needed to understand the cause-effect relationship between CeVD, white matter damage and cognition.

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Diffusion tensor tractography of the temporal stem on the inferior limiting sulcus

Journal of Neurosurgery ◽

10.3171/jns/2008/108/4/0775 ◽

2008 ◽

Vol 108 (4) ◽

pp. 775-781 ◽

Cited By ~ 26

Author(s):

Feng Wang ◽

Tao Sun ◽

Xing-Gang Li ◽

Na-Jia Liu

Keyword(s):

White Matter ◽

Diffusion Tensor ◽

Anterior Commissure ◽

Region Of Interest ◽

Diffusion Tensor Tractography ◽

Optic Radiation ◽

Uncinate Fasciculus ◽

White Matter Tracts ◽

Temporal Horn ◽

Temporal Stem

Object The aim of this study was to use diffusion tensor tractography (DTT) to define the 3D relationships of the uncinate fasciculus, anterior commissure, inferior occipitofrontal fasciculus, inferior thalamic peduncle, and optic radiation and to determine the positioning landmarks of these white matter tracts. Methods The anatomy was studied in 10 adult human brain specimens. Brain DTT was performed in 10 healthy volunteers. Diffusion tensor tractography images of the white matter tracts in the temporal stem were obtained using the simple single region of interest (ROI) and multi-ROIs based on the anatomical knowledge. Results The posteroinferior insular point is the anterior extremity of intersection of the Heschl gyrus and the inferior limiting sulcus. On the inferior limiting sulcus, this point is the posterior limit of the optic radiation, and the temporal stem begins at the limen insulae and ends at the posteroinferior insular point. The distance from the limen insulae to the tip of the temporal horn is just one third the length of the temporal stem. The uncinate fasciculus comprises the core of the anterior temporal stem, behind which the anterior commissure and the inferior thalamic peduncle are located, and they occupy the anterior third of the temporal stem. The inferior occipitofrontal fasciculus passes through the entire temporal stem. The most anterior extent of the Meyer loop is located between the anterior tip of the temporal horn and the limen insulae. Most of the optic radiation crosses the postmedian two thirds of the temporal stem. Conclusions On the inferior limiting sulcus, the posteroinferior insular point is a reliable landmark of the posterior limit of the optic radiations. The limen insulae, anterior tip of the temporal horn, and posteroinferior insular point may be used to localize the white matter fibers of the temporal stem in analyzing magnetic resonance imaging or during surgery.

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Regions of white matter abnormalities in the arcuate fasciculus in veterans with anger and aggression problems

Brain Structure and Function ◽

10.1007/s00429-019-02016-2 ◽

2019 ◽

Vol 225 (4) ◽

pp. 1401-1411 ◽

Cited By ~ 1

Author(s):

Szabolcs David ◽

Lieke Heesink ◽

Elbert Geuze ◽

Thomas Gladwin ◽

Jack van Honk ◽

...

Keyword(s):

White Matter ◽

Diffusion Tensor ◽

Military Veterans ◽

Self Regulation ◽

Brain Regions ◽

Microstructural Properties ◽

Uncinate Fasciculus ◽

Arcuate Fasciculus ◽

White Matter Connectivity ◽

Diffusion Tensor Imaging Tractography

AbstractAggression after military deployment is a common occurrence in veterans. Neurobiological research has shown that aggression is associated with a dysfunction in a network connecting brain regions implicated in threat processing and emotion regulation. However, aggression may also be related to deficits in networks underlying communication and social cognition. The uncinate and arcuate fasciculi are integral to these networks, thus studying potential abnormalities in these white matter connections can further our understanding of anger and aggression problems in military veterans. Here, we use diffusion tensor imaging tractography to investigate white matter microstructural properties of the uncinate fasciculus and the arcuate fasciculus in veterans with and without anger and aggression problems. A control tract, the parahippocampal cingulum was also included in the analyses. More specifically, fractional anisotropy (FA) estimates are derived along the trajectory from all fiber pathways and compared between both groups. No between-group FA differences are observed for the uncinate fasciculus and the cingulum, however parts of the arcuate fasciculus show a significantly lower FA in the group of veterans with aggression and anger problems. Our data suggest that abnormalities in arcuate fasciculus white matter connectivity that are related to self-regulation may play an important role in the etiology of anger and aggression in military veterans.

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A Volumetric Approach to Quantifying Region-to-Region White Matter Connectivity in Diffusion Tensor MRI

Lecture Notes in Computer Science - Information Processing in Medical Imaging ◽

10.1007/978-3-540-73273-0_29 ◽

2007 ◽

pp. 346-358 ◽

Cited By ~ 24

Author(s):

P. Thomas Fletcher ◽

Ran Tao ◽

Won-Ki Jeong ◽

Ross T. Whitaker

Keyword(s):

White Matter ◽

Diffusion Tensor ◽

Diffusion Tensor Mri ◽

White Matter Connectivity

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Brain connectivity in body dysmorphic disorder compared with controls: a diffusion tensor imaging study

Psychological Medicine ◽

10.1017/s0033291713000421 ◽

2013 ◽

Vol 43 (12) ◽

pp. 2513-2521 ◽

Cited By ~ 23

Author(s):

B. G. Buchanan ◽

S. L. Rossell ◽

J. J. Maller ◽

W. L. Toh ◽

S. Brennan ◽

...

Keyword(s):

Diffusion Tensor Imaging ◽

White Matter ◽

Body Dysmorphic Disorder ◽

Diffusion Tensor ◽

Brain Connectivity ◽

Imaging Study ◽

Healthy Controls ◽

Caudate Nuclei ◽

White Matter Connectivity ◽

The Brain

BackgroundSeveral neuroimaging studies have investigated brain grey matter in people with body dysmorphic disorder (BDD), showing possible abnormalities in the limbic system, orbitofrontal cortex, caudate nuclei and temporal lobes. This study takes these findings forward by investigating white matter properties in BDD compared with controls using diffusion tensor imaging. It was hypothesized that the BDD sample would have widespread significantly reduced white matter connectivity as characterized by fractional anisotropy (FA).MethodA total of 20 participants with BDD and 20 healthy controls matched on age, gender and handedness underwent diffusion tensor imaging. FA, a measure of water diffusion within a voxel, was compared between groups on a voxel-by-voxel basis across the brain using tract-based spatial statistics within the FSL package.ResultsResults showed that, compared with healthy controls, BDD patients demonstrated significantly lower FA (p < 0.05) in most major white matter tracts throughout the brain, including in the superior longitudinal fasciculus, inferior fronto-occipital fasciculus and corpus callosum. Lower FA levels could be accounted for by increased radial diffusivity as characterized by eigenvalues 2 and 3. No area of higher FA was found in BDD.ConclusionsThis study provided the first evidence of compromised white matter integrity within BDD patients. This suggests that there are inefficient connections between different brain areas, which may explain the cognitive and emotion regulation deficits within BDD patients.

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