Disconnections in Personal Neglect

2021 ◽  
Author(s):  
Sara Bertagnoli ◽  
Valentina Pacella ◽  
Elena Rossato ◽  
Paul M Jenkinson ◽  
Akaterini Fotopoulou ◽  
...  
Keyword(s):  
White Matter ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Lesion Size ◽  
The Body ◽  
Spatial Neglect ◽  
Small Samples ◽  
Motor Deficits ◽  
The Novel ◽  
Extrapersonal Space

Abstract Personal neglect is a disorder in the perception and representation of the body that causes the patients to behave as if the contralesional side of their body does not exist. This clinical condition has not been adequately investigated in the past as it has been considered a symptom of unilateral spatial neglect, which has mainly been studied with reference to extrapersonal space. Only a few studies with small samples have investigated the neuroanatomical correlates of personal neglect, and these have mainly focused on discrete cortical lesions and modular accounts, as well as being based on the hypothesis that this disorder is associated with somatosensory and spatial deficits. In the present study, we tested the novel hypothesis that personal neglect may be associated not only with discrete cortical and subcortical lesions, but also with disconnections of white matter tracts. We performed an advanced lesion analyses in a large sample of 104 right hemisphere damaged patients, 68 of whom were suffering from personal neglect. Results from the analyses of the grey and white matter were controlled for co-occurrent clinical variables such as extrapersonal neglect, anosognosia for hemiplegia and motor deficits, along with other lesion-related variables such as lesion size, the interval from the lesion onset to neuroimaging recordings. Our results reveal that personal neglect is associated with lesions in a medial network which involves the temporal cortex (Heschl’s gyrus), the ventro-lateral nuclei of the thalamus, and the fornix. This suggests that personal neglect involves a convergence between sensorimotor processes, spatial representation and the processing of self-referred information (episodic memory).

Development of the Halifax Visual Scanning Test: A New Measure of Visual-Spatial Neglect for Personal, Peripersonal, and Extrapersonal Space

2019 ◽  
Vol 25 (05) ◽  
pp. 490-500
Author(s):  
Christiane E. Whitehouse ◽  
Janet Green ◽  
Sarah M. Giles ◽  
Rosanna Rahman ◽  
Jamesie Coolican ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Assessment Tool ◽  
Spatial Neglect ◽  
Visual Scanning ◽  
Control Data ◽  
Normative Database ◽  
Rehabilitation Outcomes ◽  
Visual Spatial ◽  
Extrapersonal Space ◽  
Stroke Group

Objectives: Visual-spatial neglect is a common attentional disorder after right-hemisphere stroke and is associated with poor rehabilitation outcomes. The presence of neglect symptoms has been reported to vary across personal, peripersonal, and extrapersonal space. Currently, no measure is available to assess neglect severity equally across these spatial regions and may be missing subsets of symptoms or patients with neglect entirely. We sought to provide initial construct validity for a novel assessment tool that measures neglect symptoms equally for these spatial regions: the Halifax Visual Scanning Test (HVST). Methods: In Study I, the HVST was compared to conventional measures of neglect and functional outcome scores (wheelchair navigation) in 15 stroke inpatients and 14 healthy controls. In Study II, 19 additional controls were combined with the control data from Study I to establish cutoffs for impairment. Patterns of neglect in the stroke group were examined. Results: In Study I, performance on all HVST subtests were correlated with the majority of conventional subtests and wheelchair navigation outcomes. In Study II, neglect-related deficits in visual scanning showed dissociations across spatial regions. Four inpatients exhibited symptoms of neglect on the HVST that were not detected on conventional measures, one of which showed symptoms in personal and extrapersonal space exclusively. Conclusions: The HVST appears a useful measure of neglect symptoms in different spatial regions that may not be detected with conventional measures and that correlates with functional wheelchair performance. Preliminary control data are presented and further research to add to this normative database appears warranted. (JINS, 2019, 25, 490–500)

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 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.

scholarly journals Spatial frames of reference and somatosensory processing: a neuropsychological perspective

1997 ◽  
Vol 352 (1360) ◽  
pp. 1401-1409 ◽  
Author(s):  
Giuseppe Vallar
Keyword(s):  
Right Hemisphere ◽  
Higher Order ◽  
The Body ◽  
Frames Of Reference ◽  
Neural Basis ◽  
Right Brain ◽  
Extrapersonal Space ◽  
Spatial Frames Of Reference ◽  
Posterior Parietal ◽  
Sensory Processes

In patients with lesions in the right hemisphere, frequently involving the posterior parietal regions, left–sided somatosensory (and visual and motor) deficits not only reflect a disorder of primary sensory processes, but also have a higher–order component related to a defective spatial representation of the body. This additional factor, related to right brain damage, is clinically relevant: contralesional hemianaesthesia (and hemianopia and hemiplegia) is more frequent in right brain–damaged patients than in patients with damage to the left side of the brain. Three main lines of investigation suggest the existence of this higher–order pathological factor. (i) Right brain–damaged patients with left hemineglect may show physiological evidence of preserved processing of somatosensory stimuli, of which they are not aware. Similar results have been obtained in the visual domain. (ii) Direction–specific vestibular, visual optokinetic and somatosensory or proprioceptive stimulations may displace spatial frames of reference in right brain–damaged patients with left hemineglect, reducing or increasing the extent of the patients’ ipsilesional rightward directional error, and bring about similar directional effects in normal subjects. These stimulations, which may improve or worsen a number of manifestations of the neglect syndrome (such as extrapersonal and personal hemineglect), have similar effects on the severity of left somatosensory deficits (defective detection of tactile stimuli, position sense disorders). However, visuospatial hemineglect and the somatosensory deficits improved by these stimulations are independent, albeit related, disorders. (iii) The severity of left somatosensory deficits is affected by the spatial position of body segments, with reference to the midsagittal plane of the trunk. A general implication of these observations is that spatial (non–somatotopic) levels of representation contribute to corporeal awareness. The neural basis of these spatial frames includes the posterior parietal and the premotor frontal regions. These spatial representations could provide perceptual–premotor interfaces for the organization of movements (e.g. pointing, locomotion) directed towards targets in personal and extrapersonal space. In line with this view, there is evidence that the sensory stimulations that modulate left somatosensory deficits affect left motor disorders in a similar, direction–specific, fashion.

scholarly journals White Matter Integrity Correlates of the Reading Span

2021 ◽  
Author(s):  
Ekaterina V. Pechenkova ◽  
Yana R. Panikratova ◽  
Maria A. Fomina ◽  
Elena A. Mershina ◽  
Daria A. Bazhenova ◽  
...  
Keyword(s):  
Working Memory ◽  
White Matter ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
Verbal Working Memory ◽  
The Body ◽  
White Matter Integrity ◽  
Reading Span ◽  
The Right

Although working memory (WM) is crucial for intellectual abilities, not much is known about its brain underpinnings, especially the structural connectivity. We used diffusion tensor imaging (DTI) to look across the whole brain for the white matter integrity correlates of the individual differences in the reading span (verbal WM capacity during reading) in healthy adults. Right-handed healthy native Russian speakers (N = 67) underwent DTI on a 3T Philips Ingenia scanner. Verbal WM was assessed with the Daneman-Carpenter reading span test (Russian version). Fractional anisotropy maps from each participant were entered into the group tract-based spatial statistics analysis with the reading span as a covariate; the results were TFCE-corrected. After taking into account effects of age, sex, education and handedness, reading span positively correlated with the white matter integrity in multiple sites: the body, the genu and the splenium of corpus callosum; bilateral corona radiata (anterior, posterior, and superior); bilateral superior longitudinal fasciculus; several tracts in the right hemisphere only, including the internal and external capsule; bilateral superior parietal and frontal white matter. Although the left hemisphere is central for verbal processing, we revealed the important role of the right hemisphere white matter for the verbal WM capacity. Our finding indicates that larger verbal working memory span may originate from additional processing resources of the right hemisphere.

scholarly journals Disruptions of the Human Connectome Associated With Hemispatial Neglect

Neurology ◽  
2022 ◽  
Vol 98 (2) ◽  
pp. e107-e114
Author(s):  
Sadhvi Saxena ◽  
Zafer Keser ◽  
Chris Rorden ◽  
Leonardo Bonilha ◽  
Julius Fridriksson ◽  
...  
Keyword(s):  
White Matter ◽  
Parietal Cortex ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Brain Regions ◽  
Horizontal Line ◽  
Hemispatial Neglect ◽  
White Matter Tracts ◽  
The Right ◽  
Contralesional Side

Background and ObjectivesHemispatial neglect is a heterogeneous and complex disorder that can be classified by frame of reference for “left” vs “right,” including viewer-centered neglect (VCN, affecting the contralesional side of the view), stimulus-centered neglect (SCN, affecting the contralesional side of the stimulus, irrespective of its location with respect to the viewer), or both. We investigated the effect of acute stroke lesions on the connectivity of neural networks that underlie VCN or SCN.MethodsA total of 174 patients within 48 hours of acute right hemispheric infarct underwent a detailed hemispatial neglect assessment that included oral reading, scene copy, line cancellation, gap detection, horizontal line bisection tests, and MRI. Each patient's connectivity map was generated. We performed a linear association analysis between network connectivity strength and continuous measures of neglect to identify lesion-induced disconnections associated with the presence or severity of VCN and SCN. Results were corrected for multiple comparisons.ResultsAbout 42% of the participants with right hemisphere stroke had at least one type of neglect. The presence of any type of neglect was associated with lesions to tracts connecting the right inferior parietal cortex, orbitofrontal cortex, and right thalamus to other right-hemispheric structures. VCN only was strongly associated with tracts connecting the right putamen to other brain regions and tracts connecting right frontal regions with other brain regions. The presence of both types of neglect was most strongly associated with tracts connecting the right inferior and superior parietal cortex to other brain regions and those connecting left or right mesial temporal cortex to other brain regions.DiscussionOur study provides new evidence for the specific white matter tracts where disruption can cause hemispatial neglect in a relatively large number of participants and homogeneous time after onset. We obtained MRI and behavioral testing acutely, before the opportunity for rehabilitation or substantial recovery.Classification of EvidenceThis study provides Class II evidence that damage to specific white matter tracts identified on MRI are associated with the presence of neglect following right hemispheric stroke.

Unilateral Spatial Neglect

2014 ◽  
Author(s):  
Giuseppe Vallar ◽  
Nadia Bolognini
Keyword(s):  
Right Hemisphere ◽  
Parietal Lobe ◽  
The Body ◽  
Spatial Neglect ◽  
Motor Action ◽  
Unilateral Spatial Neglect ◽  
Semantic Level ◽  
The Right ◽  
Neglect Dyslexia ◽  
Contralesional Side

Left unilateral spatial neglect is the most frequent and disabling neuropsychological syndrome caused by lesions to the right hemisphere. Over 50% of right-brain-damaged patients show neglect, while right neglect after left-hemispheric damage is less frequent. Neglect patients are unable to orient towards the side contralateral to the lesion, to detect and report sensory events in that portion of space, as well as to explore it by motor action. Neglect is a multicomponent disorder, which may involve the contralesional side of the body or of extra-personal physical or imagined space, different sensory modalities, specific domains (e.g. ‘neglect dyslexia’), and worsen sensorimotor deficits. Neglect is due to higher-order unilateral deficits of spatial attention and representation, so that patients are not aware of contralesional events, which, however, undergo a substantial amount of unconscious processing up to the semantic level. Cross-modal sensory integration is also largely preserved. Neglect is primarily a spatially specific disorder of perceptual consciousness. The responsible lesions involve a network including the fronto-temporo-parietal cortex (particularly the posterior-inferior parietal lobe, at the temporo-parietal junction), their white matter connections, and some subcortical grey nuclei (thalamus, basal ganglia). Damage to primary sensory and motor regions is not associated to neglect. A variety of physiological lateralized and asymmetrical sensory stimulations (vestibular, optokinetic, prism adaptation, motor activation), and transcranial electrical and magnetic stimulations, may temporarily improve or worsen neglect. Different procedures have been successfully developed to rehabilitate neglect, using both ‘top down’ (training the voluntary orientation of attention) and ‘bottom up’ (the above-mentioned stimulations) approaches.

scholarly journals White Matter Integrity in the Right Hemisphere Correlates with the Reading Span

2021 ◽  
Author(s):  
Ekaterina Pechenkova ◽  
Yana Panikratova ◽  
Maria Fomina ◽  
Elena Mershina ◽  
Daria Bazhenova ◽  
...  
Keyword(s):  
Working Memory ◽  
White Matter ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
Verbal Working Memory ◽  
The Body ◽  
White Matter Integrity ◽  
Reading Span ◽  
The Right

Although working memory (WM) is crucial for intellectual abilities, not much is known about its brain underpinnings, especially the structural connectivity. We used diffusion tensor imaging (DTI) to look across the whole brain for the white matter integrity correlates of the individual differences in the reading span (verbal WM capacity during reading) in healthy adults. Right-handed healthy native Russian speakers (N = 47) underwent DTI on a 3T Philips Ingenia scanner. Verbal WM was assessed with the Daneman-Carpenter reading span test (Russian version). Fractional anisotropy maps from each participant were entered into the group tract-based spatial statistics analysis with the reading span as a covariate; the results were TFCE-corrected. Reading span positively correlated with the white matter integrity in several sites of the right hemisphere: the body and the splenium of corpus callosum; the posterior limb of internal capsule; posterior corona radiata; and superior parietal white matter. Although the left hemisphere is central for verbal processing, we revealed the important role of the right hemisphere white matter for the verbal WM capacity. Our finding indicates that larger verbal working memory span may originate from additional processing resources of the right hemisphere.

scholarly journals Effects of unilateral cortical resection of the visual cortex on bilateral human white matter

2019 ◽  
Author(s):  
Anne Margarette S. Maallo ◽  
Erez Freud ◽  
Tina Tong Liu ◽  
Christina Patterson ◽  
Marlene Behrmann
Keyword(s):  
White Matter ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Pediatric Epilepsy ◽  
Single Subject ◽  
List Type ◽  
Network Efficiency ◽  
White Matter Microstructure ◽  
Network Properties ◽  
Tractography Data

AbstractChildren with unilateral resections of ventral occipito-temporal cortex (VOTC) typically do not evince visual perceptual impairments, even when relatively large swathes of VOTC are resected. In search of possible explanations for this behavioral competence, we evaluated white matter microstructure and connectivity in eight pediatric epilepsy patients following unilateral cortical resection and 15 age-matched controls. To uncover both local and broader resection-induced effects, we analyzed tractography data using two complementary approaches. First, the microstructural properties were measured in the inferior longitudinal and the inferior fronto-occipital fasciculi, the major VOTC association tracts. Group differences were only evident in the ipsilesional, and not in the contralesional, hemisphere, and single-subject analyses revealed that these differences were limited to the site of the resection. Second, graph theory was used to characterize the connectivity of the contralesional occipito-temporal regions. There were no changes to the network properties in patients with left VOTC resections nor in patients with resections outside the VOTC, but altered network efficiency was observed in two cases with right VOTC resections. These results suggest that, in many, although perhaps not all, cases of unilateral VOTC resections in childhood, the white matter integrity in the preserved contralesional hemisphere along with residual neural activity might be sufficient for normal visual perception.HighlightsThere is well-circumscribed white matter damage in pediatric epilepsy after surgeryWhite matter pathways are normal distal as well as contralesional to the resectionContralesional network properties differ after left or right hemisphere resectionPreserved cortex and white matter may be sufficient for normal perception

Diaghilev and British Writing

2009 ◽  
Vol 27 (1) ◽  
pp. 65-92
Author(s):  
Susan Jones
Keyword(s):  
Visual Arts ◽  
The Body ◽  
The Novel ◽  
Literary Responses ◽  
Literary Aesthetics ◽  
Ballets Russes ◽  
The Arts ◽  
The Subject ◽  
And Gender ◽  
Opening Up

This article explores the diversity of British literary responses to Diaghilev's project, emphasising the way in which the subject matter and methodologies of Diaghilev's modernism were sometimes unexpectedly echoed in expressions of contemporary British writing. These discussions emerge both in writing about Diaghilev's work, and, more discretely, when references to the Russian Ballet find their way into the creative writing of the period, serving to anchor the texts in a particular cultural milieu or to suggest contemporary aesthetic problems in the domain of literary aesthetics developing in the period. Figures from disparate fields, including literature, music and the visual arts, brought to their criticism of the Ballets Russes their individual perspectives on its aesthetics, helping to consolidate the sense of its importance in contributing to the inter-disciplinary flavour of modernism across the arts. In the field of literature, not only did British writers evaluate the Ballets Russes in terms of their own poetics, their relationship to experimentation in the novel and in drama, they developed an increasing sense of the company's place in dance history, its choreographic innovations offering material for wider discussions, opening up the potential for literary modernism's interest in impersonality and in the ‘unsayable’, discussions of the body, primitivism and gender.

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