scholarly journals Relationship between Visual Perception and Microstructural Change of the Superior Longitudinal Fasciculus in Patients with Brain Injury in the Right Hemisphere: A Preliminary Diffusion Tensor Tractography Study

Diagnostics ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 641
Author(s):  
Su-Hong Kim ◽  
Hyeong-Eun Jeon ◽  
Chan-Hyuk Park
Keyword(s):  
Visual Perception ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Microstructural Change ◽  
Spatial Neglect ◽  
Superior Longitudinal Fasciculus ◽  
Microstructural Changes ◽  
Control Subjects ◽  
Significant Difference ◽  
The Right

Right hemisphere brain damage often results in visual-spatial deficits. Because various microstructural changes of the superior longitudinal fasciculus (SLF) after a stroke in the right hemisphere affect visual perception, including neglect, the present study investigates the relationship between both microstructural change and lateralization of SLF and visual perception, using diffusion tensor imaging (DTI) in patients with lesions in the right hemisphere. Eight patients with strokes (five patients with intracranial hemorrhage, and three patients with infarction; mean age of 52.5 years) and 16 mean-age-matched healthy control subjects were involved in this study. The visual perception of all eight patients was assessed with the motor-free visual perception test (MVPT), and their SLFs were reconstructed using DTI. The results showed that there was a significant difference between the DTI parameters of the patients and the control subjects. Moreover, patients with microstructural damage to the right SLF showed impairment of visual perception. In patients with damage to both the dorsal and ventral pathways of the right SLF, spatial neglect was present. However, although a leftward SLF asymmetry was revealed in our patients, this lateralization did not show a relationship with visual perception. In conclusion, the microstructural changes of the right SLF play an important role in visual perception, and both pathways contribute to spatial neglect, but leftward lateralization of the right SFL activity after a stroke does not contribute to general visual perception.

scholarly journals Left egocentric neglect in early subacute right-stroke patients is related to damage of the superior longitudinal fasciculus

2021 ◽  
Author(s):  
Barbara Spanò ◽  
Davide Nardo ◽  
Giovanni Giulietti ◽  
Alessandro Matano ◽  
Ilenia Salsano ◽  
...  
Keyword(s):  
White Matter ◽  
Right Hemisphere ◽  
Neural Substrates ◽  
Spatial Neglect ◽  
Stroke Patients ◽  
Superior Longitudinal Fasciculus ◽  
Unilateral Spatial Neglect ◽  
Object Based ◽  
The Right ◽  
The Relationship

AbstractA typical consequence of stroke in the right hemisphere is unilateral spatial neglect. Distinct forms of neglect have been described, such as space-based (egocentric) and object-based (allocentric) neglect. However, the relationship between these two forms of neglect is still far from being understood, as well as their neural substrates. Here, we further explore this issue by using voxel lesion symptoms mapping (VLSM) analyses on a large sample of early subacute right-stroke patients assessed with the Apples Cancellation Test. This is a sensitive test that simultaneously measures both egocentric and allocentric neglect. Behaviourally, we found no correlation between egocentric and allocentric performance, indicating independent mechanisms supporting the two forms of neglect. This was confirmed by the VLSM analysis that pointed out a link between a damage in the superior longitudinal fasciculus and left egocentric neglect. By contrast, no association was found between brain damage and left allocentric neglect. These results indicate a higher probability to observe egocentric neglect as a consequence of white matter damages in the superior longitudinal fasciculus, while allocentric neglect appears more “globally” related to the whole lesion map. Overall, these findings on early subacute right-stroke patients highlight the role played by white matter integrity in sustaining attention-related operations within an egocentric frame of reference.

Verbal comprehension deficits after right hemisphere damage

1980 ◽  
Vol 1 (3) ◽  
pp. 279-294 ◽  
Author(s):  
Daniel B. Hier ◽  
Joni Kaplan
Keyword(s):  
Educational Attainment ◽  
Sentence Comprehension ◽  
Right Hemisphere ◽  
Vocabulary Test ◽  
Verbal Comprehension ◽  
Visuospatial Deficits ◽  
Control Subjects ◽  
Right Hemisphere Damage ◽  
The Right ◽  
Grammatical Sentence

ABSTRACTWe have compared the verbal comprehension abilities of 34 right hemisphere damaged patients to 16 hospitalized control subjects of comparable age and educational attainment. The right hemisphere damaged patients performed as well as the control subjects on a vocabulary test, but were impaired in their ability to interpret proverbs and comprehend logico-grammatical sentences. Impairment on the proverbs test was the result of a decrease in the number of abstract interpretations, whereas impairment on the logico-grammatical sentence comprehension test was related to difficultes in grasping spatial and passive relationships. These comprehension impairments tended to correlate with visuospatial deficits and hemianopia, but not with the degree of hemiparesis or the presence of sensory extinction. Patients with anterior right hemisphere damage performed better on the logico-grammatical sentence conprehension test than patients with posterior damage. A variety of factors probably contribute to these verbal deficits including impaired intellect, inattention, an inability to grasp spatial relationships, and difficulties in manipulating the inner schemata of language.

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.

Brain Network Dysfunction in Poststroke Delirium and Spatial Neglect: An fMRI Study

Stroke ◽  
2021 ◽  
Author(s):  
Olga Boukrina ◽  
Mateusz Kowalczyk ◽  
Yury Koush ◽  
Yekyung Kong ◽  
A.M. Barrett
Keyword(s):  
Right Hemisphere ◽  
Functional Neuroimaging ◽  
Brain Network ◽  
Spatial Neglect ◽  
Stroke Recovery ◽  
Network Activity ◽  
Brain Disorder ◽  
Fmri Study ◽  
The Right ◽  
Right Hemisphere Stroke

Background and Purpose: Delirium, an acute reduction in cognitive functioning, hinders stroke recovery and contributes to cognitive decline. Right-hemisphere stroke is linked with higher delirium incidence, likely, due to the prevalence of spatial neglect (SN), a right-brain disorder of spatial processing. This study tested if symptoms of delirium and SN after right-hemisphere stroke are associated with abnormal function of the right-dominant neural networks specialized for maintaining attention, orientation, and arousal. Methods: Twenty-nine participants with right-hemisphere ischemic stroke undergoing acute rehabilitation completed delirium and SN assessments and functional neuroimaging scans. Whole-brain functional connectivity of 4 right-hemisphere seed regions in the cortical-subcortical arousal and attention networks was assessed for its relationship to validated SN and delirium severity measures. Results: Of 29 patients, 6 (21%) met the diagnostic criteria for delirium and 16 (55%) for SN. Decreased connectivity of the right basal forebrain to brain stem and basal ganglia predicted more severe SN. Increased connectivity of the arousal and attention network regions with the parietal, frontal, and temporal structures in the unaffected hemisphere was also found in more severe delirium and SN. Conclusions: Delirium and SN are associated with decreased arousal network activity and an imbalance of cortico-subcortical hemispheric connectivity. Better understanding of neural correlates of poststroke delirium and SN will lead to improved neuroscience-based treatment development for these disorders.

Diffusion tensor imaging of cerebral white matter in patients with myotonic dystrophy

2005 ◽  
Vol 46 (1) ◽  
pp. 104-109 ◽  
Author(s):  
H. Fukuda ◽  
J. Horiguchi ◽  
C. Ono ◽  
T. Ohshita ◽  
J. Takaba ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Myotonic Dystrophy ◽  
Normal Control ◽  
Diffusion Tensor ◽  
Age At Onset ◽  
Mean Diffusivity ◽  
Magnetic Resonance Images ◽  
Microstructural Changes ◽  
Control Subjects

Purpose: To determine whether myotonic dystrophy (MyD) patients have diffusion tensor abnormalities suggestive of microstructural changes in normal‐appearing white matter (NAWM). Material and Methods: Conventional and diffusion tensor magnetic resonance images of the brain were obtained in 19 MyD patients and 19 age‐matched normal control subjects. Fractional anisotropy (FA) and mean diffusivity (MD) values were calculated in white matter lesions (WMLs) and NAWM in MyD patients and in the white matter of normal control subjects. Differences between WML and NAWM values and between MyD patient and control subject values were analyzed statistically. Results: Significantly lower FA and higher MD values were found in all regions of interest in the NAWM of MyD patients than in the white matter of control subjects ( P<0.01), as well as significantly lower FA and higher MD values in WMLs than in NAWM of MyD patients ( P<0.05). There was no significant correlation of mean FA or MD values in NAWM with patient age, age at onset, or duration of illness ( P>0.1). Conclusion: Diffusion tensor imaging analysis suggests the presence of diffuse microstructural changes in NAWM of MyD patients that may play an important role in the development of disability.

scholarly journals Atypical Hemispheric Dominance for Attention: Functional MRI Topography

2005 ◽  
Vol 25 (9) ◽  
pp. 1197-1208 ◽  
Author(s):  
Agnes Flöel ◽  
Andreas Jansen ◽  
Michael Deppe ◽  
Martin Kanowski ◽  
Carsten Konrad ◽  
...  
Keyword(s):  
Spatial Attention ◽  
Right Hemisphere ◽  
Regional Distribution ◽  
Visuospatial Attention ◽  
Hemispheric Dominance ◽  
Neural Activation ◽  
Brain Organization ◽  
Attention Task ◽  
Control Subjects ◽  
The Right

The right hemisphere is predominantly involved in tasks associated with spatial attention. However, left hemispheric dominance for spatial attention can be found in healthy individuals, and both spatial attention and language can be lateralized to the same hemisphere. Little is known about the underlying regional distribution of neural activation in these ‘atypical’ individuals. Previously a large number of healthy subjects were screened for hemispheric dominance of visuospatial attention and language, using functional Doppler ultrasonography. From this group, subjects were chosen who were ‘atypical’ for hemispheric dominance of visuospatial attention and language, and their pattern of brain activation was studied with functional magnetic resonance imaging during a task probing spatial attention. Right-handed subjects with the ‘typical’ pattern of brain organization served as control subjects. It was found that subjects with an inverted lateralization of language and spatial attention (language right, attention left) recruited left-hemispheric areas in the attention task, homotopic to those recruited by control subjects in the right hemisphere. Subjects with lateralization of both language and attention to the right hemisphere activated an attentional network in the right hemisphere that was comparable to control subjects. The present findings suggest that not the hemispheric side, but the intrahemispheric pattern of activation is the distinct feature for the neural processes underlying language and attention.

Alpha Asymmetry over the Right and Left Hemispheres of Stutterers and Control Subjects Preceding Massed Oral Readings: A Preliminary Investigation

1977 ◽  
Vol 44 (1) ◽  
pp. 223-230 ◽  
Author(s):  
W. H. Moore ◽  
Mary K. Lang
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Preliminary Investigation ◽  
Hemispheric Processing ◽  
Preliminary Results ◽  
Alpha Asymmetry ◽  
Control Subjects ◽  
The Right ◽  
And Control

Interhemispheric alpha asymmetry of both stutterers and non-stutterers measured preceding each of five massed oral readings of the same material was investigated. Preliminary results indicated a reduction of alpha over the left hemisphere for non-stutterers, while a reduction for stutterers was found for the right hemisphere. Present results, together with other investigations using dichotic, tachistoscopic, and EEG procedures, suggest right hemispheric processing for the stuttering group as compared with left hemispheric processing for the non-stuttering group.

scholarly journals Microstructural Abnormalities of Substantia Nigra in Parkinson’s disease: A Neuromelanin Sensitive MRI Atlas Based Study

2019 ◽  
Author(s):  
Apoorva Safai ◽  
Shweta Prasad ◽  
Jitender Saini ◽  
Pramod Kumar Pal ◽  
Madhura Ingalhalikar
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Substantia Nigra ◽  
Diffusion Tensor ◽  
Region Of Interest ◽  
Substantia Nigra Pars Compacta ◽  
Microstructural Changes ◽  
Severity Scores ◽  
Mri Sequences ◽  
The Right

AbstractMicrostructural changes associated with degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNc) in Parkinson’s disease (PD) have been studied using Diffusion Tensor Imaging (DTI). However, these studies show inconsistent results, mainly due to methodological variations in delineation of SNc. To mitigate this, our work aims to construct a probabilistic atlas of SNc based on a Neuromelanin sensitive MRI (NMS-MRI) sequence and demonstrate its applicability to investigate microstructural changes on a large dataset of PD. Using manual segmentation and deformable registrations, we create a novel SNc atlas in the MNI space using NMS-MRI sequences of 27 healthy controls (HC). We employ this atlas to evaluate the diffusivity and anisotropy measures, derived from diffusion MRI in the SNc of 135 patients with PD and 99 HCs. Our observations of significantly increased diffusivity measures provide evidence of microstructural abnormalities in PD. However, no changes in the anisotropy were observed. Moreover, the asymmetry in abnormalities is prominent as the left SNc showed significant increase in diffusivity, and a reduction in FA when compared to the right SNc. Further the diffusivity and FA values also demonstrated a trend when correlated with the PD severity scores. Overall, from this work we establish a normative baseline for the SNc region of interest using NMS-MRI while the application on PD data emphasizes on the contribution of diffusivity measures rather than anisotropy of white matter in PD.

scholarly journals Age dependency and lateralization in the three branches of the human superior longitudinal fasciculus

2021 ◽  
Author(s):  
Kaoru Amemiya ◽  
Eiichi Naito ◽  
Hiromasa Takemura
Keyword(s):  
Right Hemisphere ◽  
Age Groups ◽  
White Matter Tract ◽  
Age Dependency ◽  
Diffusion Weighted Mri ◽  
Superior Longitudinal Fasciculus ◽  
Wide Range ◽  
Adolescents And Adults ◽  
The Right ◽  
Parietal Cortices

AbstractThe superior longitudinal fascicle/fasciculus (SLF) is a major white matter tract connecting the frontal and parietal cortices in humans. Although the SLF has often been analyzed as a single entity, several studies have reported that the SLF is segregated into three distinct branches (SLF I, II, and III). They have also reported the right lateralization of the SLF III volume and discussed its relationship with lateralized cortical functions in the fronto-parietal network. However, to date, the homogeneity or heterogeneity of the age dependency and lateralization properties of SLF branches have not been fully clarified. Through this study, we aimed to clarify the age dependency and lateralization of SLF I-III by analyzing diffusion-weighted MRI (dMRI) and quantitative R1 (qR1) map datasets collected from a wide range of age groups, mostly comprising right-handed children, adolescents, adults, and seniors (6 to 81 years old). The age dependency in dMRI measurement (fractional anisotropy, FA) was heterogeneous among the three SLF branches, suggesting that these branches are regulated by distinct developmental and aging processes. Lateralization analysis on SLF branches revealed that the right SLF III was larger than the left SLF III in adults, replicating previous reports. FA measurement also suggested that, in addition to SLF III, SLF II was lateralized to the right hemisphere in adolescents and adults. We further found a left lateralization of SLF I in qR1 data, a microstructural measurement sensitive to myelin levels, in adults. These findings suggest that the SLF sub-bundles are distinct entities in terms of age dependency and lateralization.

Sign in / Sign up

Export Citation Format

Share Document