scholarly journals The Role of the Right Hemisphere White Matter Tracts in Chronic Aphasic Patients After Damage of the Language Tracts in the Left Hemisphere

2021 ◽  
Vol 15 ◽  
Author(s):  
Evie Kourtidou ◽  
Dimitrios Kasselimis ◽  
Georgia Angelopoulou ◽  
Efstratios Karavasilis ◽  
Georgios Velonakis ◽  
...  
Keyword(s):  
White Matter ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Language Performance ◽  
White Matter Tracts ◽  
Post Stroke ◽  
Language Functions ◽  
The Right

The involvement of the right hemisphere (RH) in language, and especially after aphasia resulting from left hemisphere (LH) lesions, has been recently highlighted. The present study investigates white matter structure in the right hemisphere of 25 chronic post-stroke aphasic patients after LH lesions in comparison with 24 healthy controls, focusing on the four cortico-cortical tracts that link posterior parietal and temporal language-related areas with Broca’s region in the inferior frontal gyrus of the LH: the Superior Longitudinal Fasciculi II and III (SLF II and SLF III), the Arcuate Fasciculus (AF), and the Temporo-Frontal extreme capsule Fasciculus (TFexcF). Additionally, the relationship of these RH white matter tracts to language performance was examined. The patients with post-stroke aphasia in the chronic phase and the healthy control participants underwent diffusion tensor imaging (DTI) examination. The aphasic patients were assessed with standard aphasia tests. The results demonstrated increased axial diffusivity in the RH tracts of the aphasic patients. Patients were then divided according to the extent of the left hemisphere white matter loss. Correlations of language performance with radial diffusivity (RD) in the right hemisphere homologs of the tracts examined were demonstrated for the TFexcF, SLF III, and AF in the subgroup with limited damage to the LH language networks and only with the TFexcF in the subgroup with extensive damage. The results argue in favor of compensatory roles of the right hemisphere tracts in language functions when the LH networks are disrupted.

scholarly journals Multiple sclerosis and depressive manifestations: can diffusion tensor MR imaging help in the detection of microstructural white matter changes?

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Talaat A. Hassan ◽  
Shaima Fattouh Elkholy ◽  
Bahaa Eldin Mahmoud ◽  
Mona ElSherbiny
Keyword(s):  
Multiple Sclerosis ◽  
Depressive Symptoms ◽  
White Matter ◽  
Limbic System ◽  
Diffusion Tensor ◽  
Control Group ◽  
Uncinate Fasciculus ◽  
White Matter Tracts ◽  
Significant Difference ◽  
The Right

Abstract Background Multiple sclerosis is one of the commonest causes of neurological disability in middle-aged and young adults. Depression in MS patients can compromise cognitive functions, lead to suicide attempts, impair relationships and reduce compliance with disease-modifying treatments. The aim of this study was to investigate and compare the microstructural changes in the white matter tracts of the limbic system in MS patients with and those without depressive manifestations using a diffusion tensor imaging (DTI) technique. Methods This study included 40 patients who were divided into three groups. Group 1 comprised of 20 patients with relapsing-remitting MS with depressive symptoms and group 2 comprised 10 MS patients without symptoms of depression. The third group is a control group that included 10 age-matched healthy individuals. All patients underwent conventional MRI examinations and DTI to compare the fractional anisotropy (FA) values in the white matter tracts of the limbic system. Results We compared the DTI findings in MS patients with and those without depressive symptoms. It was found that patients with depression and MS exhibited a significant reduction in the FA values of the cingulum (P < 0.0111 on the right and P < 0.0142 on the left), uncinate fasciculus (P < 0.0001 on the right and P < 0.0076 on the left) and the fornix (P < 0.0001 on both sides). No significant difference was found between the FA values of the anterior thalamic radiations in both groups. Conclusion Patients with depression and MS showed more pronounced microstructural damage in the major white matter connections of the limbic pathway, namely, the uncinate fasciculus, cingulum and fornix. These changes can be detected by DTI as decreased FA values in depressed MS patients compared to those in non-depressed patients.

scholarly journals Transcranial brain stimulation (TMS and tDCS) for post-stroke aphasia rehabilitation: Controversies

2014 ◽  
Vol 8 (3) ◽  
pp. 207-215 ◽  
Author(s):  
Lucia Iracema Zanotto de Mendonça
Keyword(s):  
Left Hemisphere ◽  
Brain Stimulation ◽  
Right Hemisphere ◽  
Post Stroke ◽  
Transcranial Brain Stimulation ◽  
The Right ◽  
Dominance Pattern ◽  
Causal Event ◽  
Hemispheric Language Dominance ◽  
Language Network

Transcranial brain stimulation (TS) techniques have been investigated for use in the rehabilitation of post-stroke aphasia. According to previous reports, functional recovery by the left hemisphere improves recovery from aphasia, when compared with right hemisphere participation. TS has been applied to stimulate the activity of the left hemisphere or to inhibit homotopic areas in the right hemisphere. Various factors can interfere with the brain's response to TS, including the size and location of the lesion, the time elapsed since the causal event, and individual differences in the hemispheric language dominance pattern. The following questions are discussed in the present article: [a] Is inhibition of the right hemisphere truly beneficial?; [b] Is the transference of the language network to the left hemisphere truly desirable in all patients?; [c] Is the use of TS during the post-stroke subacute phase truly appropriate? Different patterns of neuroplasticity must occur in post-stroke aphasia.

scholarly journals Right Hemisphere Grey Matter Volume and Language Functions in Stroke Aphasia

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Sladjana Lukic ◽  
Elena Barbieri ◽  
Xue Wang ◽  
David Caplan ◽  
Swathi Kiran ◽  
...  
Keyword(s):  
Grey Matter ◽  
Right Hemisphere ◽  
Language Ability ◽  
Grey Matter Volume ◽  
Lesion Site ◽  
Language Performance ◽  
Support Functions ◽  
Language Functions ◽  
Lesion Symptom Mapping ◽  
The Right

The role of the right hemisphere (RH) in recovery from aphasia is incompletely understood. The present study quantified RH grey matter (GM) volume in individuals with chronic stroke-induced aphasia and cognitively healthy people using voxel-based morphometry. We compared group differences in GM volume in the entire RH and in RH regions-of-interest. Given that lesion site is a critical source of heterogeneity associated with poststroke language ability, we used voxel-based lesion symptom mapping (VLSM) to examine the relation between lesion site and language performance in the aphasic participants. Finally, using results derived from the VLSM as a covariate, we evaluated the relation between GM volume in the RH and language ability across domains, including comprehension and production processes both at the word and sentence levels and across spoken and written modalities. Between-subject comparisons showed that GM volume in the RH SMA was reduced in the aphasic group compared to the healthy controls. We also found that, for the aphasic group, increased RH volume in the MTG and the SMA was associated with better language comprehension and production scores, respectively. These data suggest that the RH may support functions previously performed by LH regions and have important implications for understanding poststroke reorganization.

Relations between White Matter Maturation and Reaction Time in Childhood

2013 ◽  
Vol 20 (1) ◽  
pp. 99-112 ◽  
Author(s):  
Nadia Scantlebury ◽  
Todd Cunningham ◽  
Colleen Dockstader ◽  
Suzanne Laughlin ◽  
William Gaetz ◽  
...  
Keyword(s):  
Information Processing ◽  
Reaction Time ◽  
White Matter ◽  
Left Hemisphere ◽  
Processing Speed ◽  
Right Hemisphere ◽  
Optic Radiation ◽  
Information Processing Speed ◽  
White Matter Maturation ◽  
The Right

AbstractWhite matter matures with age and is important for the efficient transmission of neuronal signals. Consequently, white matter growth may underlie the development of cognitive processes important for learning, including the speed of information processing. To dissect the relationship between white matter structure and information processing speed, we administered a reaction time task (finger abduction in response to visual cue) to 27 typically developing, right-handed children aged 4 to 13. Magnetoencephalography and Diffusion Tensor Imaging were used to delineate white matter connections implicated in visual-motor information processing. Fractional anisotropy (FA) and radial diffusivity (RD) of the optic radiation in the left hemisphere, and FA and mean diffusivity (MD) of the optic radiation in the right hemisphere changed significantly with age. MD and RD decreased with age in the right inferior fronto-occipital fasciculus, and bilaterally in the cortico-spinal tracts. No age-related changes were evident in the inferior longitudinal fasciculus. FA of the cortico-spinal tract in the left hemisphere and MD of the inferior fronto-occipital fasciculus of the right hemisphere contributed uniquely beyond the effect of age in accounting for reaction time performance of the right hand. Our findings support the role of white matter maturation in the development of information processing speed. (JINS, 2013, 19, 1–14)

scholarly journals Reduction in White Matter Connectivity, Revealed by Diffusion Tensor Imaging, May Account for Age-related Changes in Face Perception

2008 ◽  
Vol 20 (2) ◽  
pp. 268-284 ◽  
Author(s):  
Cibu Thomas ◽  
Linda Moya ◽  
Galia Avidan ◽  
Kate Humphreys ◽  
Kwan Jin Jung ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Face Perception ◽  
Face Processing ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Temporal Cortex ◽  
Age Related ◽  
The Right ◽  
White Matter Connectivity

An age-related decline in face processing, even under conditions in which learning and memory are not implicated, has been well documented, but the mechanism underlying this perceptual alteration remains unknown. Here, we examine whether this behavioral change may be accounted for by a reduction in white matter connectivity with age. To this end, we acquired diffusion tensor imaging data from 28 individuals aged 18 to 86 years and quantified the number of fibers, voxels, and fractional anisotropy of the two major tracts that pass through the fusiform gyrus, the pre-eminent face processing region in the ventral temporal cortex. We also measured the ability of a subset of these individuals to make fine-grained discriminations between pairs of faces and between pairs of cars. There was a significant reduction in the structural integrity of the inferior fronto-occipital fasciculus (IFOF) in the right hemisphere as a function of age on all dependent measures and there were also some changes in the left hemisphere, albeit to a lesser extent. There was also a clear age-related decrement in accuracy of perceptual discrimination, especially for more challenging perceptual discriminations, and this held to a greater degree for faces than for cars. Of greatest relevance, there was a robust association between the reduction of IFOF integrity in the right hemisphere and the decline in face perception, suggesting that the alteration in structural connectivity between the right ventral temporal and frontal cortices may account for the age-related difficulties in face processing.

scholarly journals Interpersonal Competence in Young Adulthood and Right Laterality in White Matter

2014 ◽  
Vol 26 (6) ◽  
pp. 1257-1265 ◽  
Author(s):  
Nicola De Pisapia ◽  
Mauro Serra ◽  
Paola Rigo ◽  
Justin Jager ◽  
Nico Papinutto ◽  
...  
Keyword(s):  
White Matter ◽  
Fractional Anisotropy ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Brain Lesion ◽  
Direct Analysis ◽  
Social Contexts ◽  
Interpersonal Competence ◽  
The Right ◽  
Interpersonal Competencies

The right hemisphere of the human brain is known to be involved in processes underlying emotion and social cognition. Clinical neuropsychology investigations and brain lesion studies have linked a number of personality and social disorders to abnormal white matter (WM) integrity in the right hemisphere. Here, we tested the hypothesis that interpersonal competencies are associated with integrity of WM tracts in the right hemisphere of healthy young adults. Thirty-one participants underwent diffusion tensor imaging scanning. Fractional anisotropy was used to quantify water diffusion. After the scanning session, participants completed the Adolescent Interpersonal Competence Questionnaire. Fractional anisotropy was subsequently correlated with Adolescent Interpersonal Competence Questionnaire scores using tract-based spatial statistics. Higher interpersonal competencies are related to higher WM integrity in several major tracts of the right hemisphere, in specific the uncinate fasciculus, the cingulum, the forceps minor, the infero-fronto occipital fasciculus, the inferior longitudinal fasciculus, and the superior longitudinal fasciculus. These results provide the first direct analysis of the neuroanatomical basis of interpersonal competencies and young adult self-reported skills in social contexts.

scholarly journals White Matter Abnormalities in Body Integrity Dysphoria

2021 ◽  
Author(s):  
Gianluca Saetta ◽  
Kathy Ruddy ◽  
Laura Zapparoli ◽  
Martina Gandola ◽  
Gerardo Salvato ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Structural Connectivity ◽  
The Body ◽  
Limb Amputation ◽  
Middle Temporal Gyrus ◽  
Imaging Data ◽  
Severe Condition ◽  
The Right

Body integrity dysphoria (BID) is a severe condition affecting non-psychotic individuals where a limb may be experienced as non-belonging, despite normal anatomical development and intact sensorimotor functions. Limb amputation is desired for restoring their own identity. We previously demonstrated altered brain structural (gray matter) and functional connectivity in 16 men with a long-lasting and exclusive desire for left leg amputation. Here we aimed to identify in the same sample altered patterns of white matter structural connectivity. Fractional anisotropy (FA), derived from Diffusion Tensor Imaging data, was considered as a measure of structural connectivity. Results showed reduced structural connectivity of: i) the right superior parietal lobule (rSPL) with the right cuneus, superior occipital and posterior cingulate gyri, and cuneus, ii) the pars orbitalis of the right middle frontal gyrus (rMFGOrb) with the putamen iii) the left middle temporal gyrus (lMTG) with the pars triangularis of the left inferior frontal gyrus. Increased connectivity was observed between the right paracentral lobule (rPLC) and the right caudate nucleus. By using a complementary method of investigation, we confirmed and extended previous results showing alterations in areas tuned to the processing of the sensorimotor representations of the affected leg (rPCL), and to higher-order components of bodily representation such as the body image (rSPL). Alongside this network for bodily awareness, other networks such as the limbic (rMFGOrb) and the mirror (lMTG) systems showed structural alterations as well. These findings consolidate current understanding of the neural correlates of BID, which might in turn guide diagnostics and rehabilitative treatments.

scholarly journals Sensory processing sensitivity and axonal microarchitecture: Identifying brain structural characteristics for behavior

2021 ◽  
Author(s):  
Szabolcs David ◽  
Lucy L Brown ◽  
Anneriet M Heemskerk ◽  
Elaine Aron ◽  
Alexander Leemans ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Sensory Processing ◽  
Diffusion Tensor ◽  
Structural Characteristics ◽  
Inferior Frontal Gyrus ◽  
Mean Diffusivity ◽  
Human Connectome Project ◽  
Sensory Processing Sensitivity ◽  
The Right

Previously, researchers used functional MRI to identify regional brain activations associated with sensory processing sensitivity (SPS), a proposed normal phenotype trait. To further validate SPS as a behavioral entity, to characterize it anatomically, and to test the usefulness in psychology of methodologies that assess axonal properties, the present study correlated SPS proxy questionnaire scores (adjusted for neuroticism) with diffusion tensor imaging measures. Participants (n=408) from the Young Adult Human Connectome Project that are free of neurologic and psychiatric disorders were investigated. We computed mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD) and fractional anisotropy (FA). A voxelwise, exploratory analysis showed that MD and RD correlated positively with SPS proxy scores in the right and left subcallosal and anterior ventral cingulum bundle, and the right forceps minor of the corpus callosum (peak Cohens D effect size = 0.269). Further analyses showed correlations throughout the entire right and left ventromedial prefrontal cortex, including the superior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate and arcuate fasciculus. These prefrontal regions are generally involved in emotion, reward and social processing. FA was negatively correlated with SPS proxy scores in white matter of the right premotor/motor/somatosensory/supramarginal gyrus regions, which are associated with empathy, theory of mind, primary and secondary somatosensory processing. Region of interest (ROI) analysis, based-on previous fMRI results and Freesurfer atlas-defined areas, showed small effect sizes, (+0.151 to -0.165) in white matter of the precuneus and inferior frontal gyrus. Other ROI effects were found in regions of the dorsal and ventral visual pathways and primary auditory cortex. The results reveal that in a large, diverse group of participants axonal microarchitectural differences can be identified with SPS traits that are subtle and in the range of typical behavior. The results suggest that the heightened sensory processing in people who show SPS may be influenced by the microstructure of white matter in specific neocortical regions. Although previous fMRI studies had identified most of these general neocortical regions, the DTI results put a new focus on brain areas related to attention and cognitive flexibility, empathy, emotion and low-level sensory processing, as in the primary sensory cortex. Psychological trait characterization may benefit from diffusion tensor imaging methodology by identifying influential brain systems for traits.

scholarly journals Diffusion Kurtosis Imaging Fiber Tractography of Major White Matter Tracts in Neurosurgery

2021 ◽  
Vol 11 (3) ◽  
pp. 381
Author(s):  
Miriam H. A. Bopp ◽  
Julia Emde ◽  
Barbara Carl ◽  
Christopher Nimsky ◽  
Benjamin Saß
Keyword(s):  
White Matter ◽  
Corticospinal Tract ◽  
Diffusion Tensor ◽  
Clinical Applications ◽  
Diffusion Kurtosis Imaging ◽  
Fiber Tractography ◽  
White Matter Tracts ◽  
The Right ◽  
Diffusion Kurtosis ◽  
Diffusion Tensor Imaging Dti

Diffusion tensor imaging (DTI)-based fiber tractography is routinely used in clinical applications to visualize major white matter tracts, such as the corticospinal tract (CST), optic radiation (OR), and arcuate fascicle (AF). Nevertheless, DTI is limited due to its capability of resolving intra-voxel multi-fiber populations. Sophisticated models often require long acquisition times not applicable in clinical practice. Diffusion kurtosis imaging (DKI), as an extension of DTI, combines sophisticated modeling of the diffusion process with short acquisition times but has rarely been investigated in fiber tractography. In this study, DTI- and DKI-based fiber tractography of the CST, OR, and AF was investigated in healthy volunteers and glioma patients. For the CST, significantly larger tract volumes were seen in DKI-based fiber tractography. Similar results were obtained for the OR, except for the right OR in patients. In the case of the AF, results of both models were comparable with DTI-based fiber tractography showing even significantly larger tract volumes in patients. In the case of the CST and OR, DKI-based fiber tractography contributes to advanced visualization under clinical time constraints, whereas for the AF, other models should be considered.

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