Neglect

doi:10.1016/0959-4388(94)90078-7

Current Opinion in Neurobiology

Volume 4, Issue 2, 1994, Pages 231-236

https://doi.org/10.1016/0959-4388(94)90078-7 Get rights and content

Abstract

Neglect is a disorder of orienting in which patients are unaware of objects in their contralesional visual field. Yet their pre-attentive vision is still able to parse the scene to segregate figure from ground, group objects, and define their primary axis. Therefore, it appears that perceptual processing may be intact up to the level of semantic classification, and that neglect only acts at the level of selection for action and access to awareness. Several mechanisms contribute to neglect, including disinhibited orienting to the ipsilesional field, a deranged representation of space, and deficits in disengaging attention, oculomotor corollary discharge, and representation of contralesional movement trajectories. Recent studies have begun to identify the neural substrates involved in these mechanisms.

References (57)

E. Ladavas et al.
Unilateral Attention Deficits and Hemispheric Asymmetries in the Control of Visual Attention
Neuropsychologia
(1989)
P.D. D'Erme et al.
Early Rightward Orienting of Attention on Simple Reaction Time Performance in Patients with LeftSided Neglect
Neuropsychologia
(1992)
E. Bisiach et al.
Unilateral Neglect of Representational Space
Cortex
(1978)
E. Bisiach et al.
Unilateral Neglect, Representational Schema and Consciousness
Brain
(1979)
H.O. Karnath et al.
Decrease of Contralateral Neglect by Neck Muscle Vibration and Spatial Orientation of Trunk Midline
Brain
(1993)
Egly R, Driver J, Rafal R.: Shifting Visual Attention between Objects and Locations: Evidence from Normal and Parietal...
S. Weintraub et al.
Right Cerebral Hemisphere Dominance in Spatial Attention
Arch Neurol
(1987)
J. Duhamel et al.
Saccadic Dysmetria in a Patient with a Right Frontoparietal Lesion
Brain
(1992)
M. Grabowecky et al.
Preattentive Processes Guide Visual Search: Evidence from Patients with Unilateral Visual Neglect
J Cogn Neurosci
(1993)
M.I. Posner et al.
Effects of Parietal Injury on Covert Orienting of Visual Attention
J Neurosci
(1984)

M.I. Posner et al.

How Do the Parietal Lobes Direct Covert Attention?

Neuropsychologia

(1987)

E. Ladavas

Selective Spatial Attention in Patients with Visual Extinction

Brain

(1990)

E. Ladavas et al.

The Deployment of Visual Attention in the Intact Field of Hemineglect

Cortex

(1990)

A. Chamorro et al.

Visual Hemineglect and Hemihallucinations in a Patient with Subcortical Infarction

Neurology

(1990)

M.M. Mesulam

A Cortical Network for Directed Attention and Unilateral Neglect

Ann Neurol

(1981)

F. Doricci et al.

Disappearance of Left-Ward Rapid Eye Movements during Sleep in Hemi-Inattention

Neuroreport

(1991)

E. Bisiach

Mental Representation in Unilateral Neglect and Related Disorders: the Twentieth Bartlett Memorial Lecture

Q J Exp Psychol [A]

(1993)

M. Kinsbourne

Orientational Bias Model of Unilateral Neglect: Evidence from Attentional Gradients within Hemispace

A.B. Rubens

Caloric Stimulation and Unilateral Visual Neglect

Neurology

(1985)

S.F. Cappa et al.

Remission of Hemineglect and Anosognosia after Vestibular Stimulation

Neuropsychologia

(1987)

G. Vallar et al.

Exploring Somatosensory Hemineglect by Vestibular Stimulation

Brain

(1993)

E. Bisiach et al.

Remission of Somatoparaphrenic Delusion through Vestibular Stimulation

Neuropsychologia

(1991)

L. Pizzamiglio et al.

Effect of Optokinetic Stimulation in Patients with Visual Neglect

Cortex

(1990)

K. Baynes et al.

Components of Visual Attention: Alterations in Response Pattern to Visual Stimuli following Parietal Lobe Infarction

Brain

(1986)

M.J. Farah et al.

Parietal Lobe Mechanisms of Spatial Attention: Modality-Specific or Supramodal?

Neuropsychologia

(1989)

A.W. Inhoff et al.

Bimodal Extinction without Cross Modal Extinction

J Neurol Neurosurg Psychiatry

(1992)

G. Vallar

The Anatomical Basis of Spatial Neglect in Humans

L.C. Robertson et al.

Effects of Lesions of the Temporal-Parietal junction on Perceptual and Attentional Processing in Humans

J Neurosci

(1988)

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Attentional signals projecting centrifugally to the avian retina: A dual contribution to visual search
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Among vertebrates, birds have a particularly well-developed retinopetal system, i.e., the centrifugal system projecting from the brain to the retina. Primary, secondary and tertiary neurons of the retinopetal system connect serially in a one-to-one-to-one fashion, thereby assembling several thousand retinopetal modules projecting in parallel to the retina. The signal conveyed by the retinopetal system enhances the visual responses of retinal ganglion cells (RGCs), and each retinopetal module may facilitate the RGCs in a topographically restricted area. We investigated how the retinopetal signal contributes to visual search by first training Japanese quail to search and peck a target stimulus presented on one of three touch-sensor monitors around the bird and then examining the effect of retinopetal signal blockage on the task. Our results indicate that the retinopetal signal improves both stimulus detectability and target discriminability. Thus, this study confirms that the avian retinopetal system functions specifically in attentional facilitation of the retina; this new finding suggests that this system benefits early detection and late selection phases of visual search. The fast and precise target detection facilitated by the retinopetal signal may be transformed into quick and correct orienting to the target through visuomotor transformation mechanisms implemented in the optic tectum.
Rightward exogenous attentional shifts impair perceptual memory of spatial locations in patients with left unilateral spatial neglect
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Spatial remapping implies the updating and maintaining of the spatial position of objects in successive visual images across time, despite their displacement on the retina due to eye movements. In the parietal cortex, the representation of spatial locations appears to be partly centered on gaze direction, and thus modulated by current eye-gaze position. It has been suggested that short-term memory for spatial locations across delays might be impaired in right brain-injured patients with left spatial neglect, but more so after rightward than leftward gaze shifts – an asymmetry attributed to a loss of spatial representations normally transferred from left to right hemisphere during remapping. Because several studies point to a strong link between attentional and oculomotor circuits in the brain, we hypothesized that similar remapping effects might result from attentional displacements without overt eye movements. We tested this hypothesis in right-brain damaged patients with and without left neglect in a visuo-spatial memory task. As predicted, neglect patients showed a selective deficit in location memory following an exogenous attentional shift caused by a brief flash in the periphery of their right (but not left) visual field. We conclude that an attentional displacement without eye movements is sufficient to remap spatial representations across hemifields, and that this process is impaired in neglect patients when a location has to be transferred to the neglected/left side relative to current gaze or attention focus. More generally, these results support the notion of neural overlap between oculomotor and attentional mechanisms, and confirm a role for impaired remapping in the neglect syndrome, wherein spatial representations of contralesional locations may fail to be maintained during active attentional behavior.
Representation of shape, space, and attention in monkey cortex
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Attentional deficits are core to numerous developmental, neurological, and psychiatric disorders. At the single-cell level, much knowledge has been garnered from studies of shape and spatial properties, as well as from numerous demonstrations of attentional modulation of those properties. Despite this wealth of knowledge of single-cell responses across many brain regions, little is known about how these cellular characteristics relate to population level representations and how such representations relate to behavior; in particular, how these cellular responses relate to the representation of shape, space, and attention, and how these representations differ across cortical areas and streams. Here we will emphasize the role of population coding as a missing link for connecting single-cell properties with behavior. Using a data-driven intrinsic approach to population decoding, we show that both ‘what’ and ‘where’ cortical visual streams encode shape, space, and attention, yet demonstrate striking differences in these representations. We suggest that both pathways fully process shape and space, but that differences in representation may arise due to their differing functions and input and output constraints. Moreover, differences in the effects of attention on shape and spatial population representations in the two visual streams suggest two distinct strategies: in a ventral area, attention or task demands modulate the population representations themselves (perhaps to expand or enhance one part at the expense of other parts) while in a dorsal area, at a population representation level, attention effects are weak and nearly non-existent, perhaps in order to maintain veridical representations needed for visuomotor control. We show that an intrinsic approach, as opposed to theory-driven and labeled approaches, is useful for understanding how representations develop and differ across brain regions. Most importantly, these approaches help link cellular properties more tightly with behavior, a much-needed step to better understand and interpret cellular findings and key to providing insights to improve interventions in human disorders.
Ipsilesional perceptual deficits in hemispatial neglect: Case reports
2020, Cortex
Citation Excerpt :
Hemispatial neglect is most often observed in stroke patients with right hemisphere inferior parietal or superior temporal lesions (Karnath, Berger, Küker, & Rorden, 2004; Karnath, Ferber, & Himmelbach, 2001; Lunven & Bartolomeo, 2017; Mort et al., 2003). The disorder is characterized by a profound deficit in perception on the side of space opposite the lesion (Driver & Mattingley, 1998; Rafal, 1994). For example, neglect patients may fail to notice people on their left, may eat food only from the right halves of their plates, and may fail to shave or put make up on the left half of their faces.
Hemispatial neglect, usually after right hemisphere lesions, is characterized by contralesional deficits in attention and perception. However, little is known about impairments of perceptual processing in the ipsilesional region of visual space (the right visual field for right hemisphere lesions). In two right hemisphere neglect patients, we used a metacontrast masking paradigm to characterize systematic spatial and temporal visual processing deficits in the ipsilesional right visual field. The presence of a visual mask caused the neglect patients to miss targets in ipsilesional space, even when a mask was presented as long as 1.5 sec after the target and in a different spatial position. These prolonged and spatially extended masking effects were not measured in age-matched healthy controls or in two control patients with hemianopsia but without neglect. The results show that perceptual processing is distorted and delayed in a region of the visual field that has been thought to be unaffected – the ipsilesional hemifield in patients with neglect.
Right hemisphere superiority for executive control of attention
2020, Cortex
Over forty years have passed since the first evidence showing the unbalanced attentional allocation of humans across the two visual fields, and since then, a wealth of behavioral, neurophysiological, and clinical data increasingly showed a right hemisphere dominance for orienting of attention. However, inconsistent evidence exists regarding the right-hemisphere dominance for executive control of attention, possibly due to a lack of consideration of its dynamics with the alerting and orienting functions. In this study, we used a version of the Attentional Network Test with lateralized presentation of the stimuli to the left visual field (processed by the right hemisphere, RH) and right visual field (processed by the left hemisphere, LH) to examine visual field differences in executive control of attention under alerting and orienting of attention. Analyses of behavioral performance (reaction time and error rate) showed a more efficient executive control (reduced conflict effect) in the RH compared to the LH for the reaction time, under conditions of increased alerting and of informative spatial orienting. These results demonstrate the right-hemisphere superiority for executive control, and that this effect depends on the involvement of the alerting and orienting functions.
Reward sensitivity predicts dopaminergic response in spatial neglect
2020, Cortex
Citation Excerpt :
Moreover, such neglect-like symptoms in animals can be modulated by dopaminergic stimulation (van Vleet, Heldt, Corwin, & Reep, 2003). Neuroanatomical studies of clinical neglect have understandably tended to focus on frontoparietal networks involved in spatial and non-spatial aspects of attention, but it is important to consider how the syndrome might result from interactions between component deficits (Rafal, 1994). Although some studies have investigated neglect solely secondary to basal ganglia damage, there have been very few clinical studies exploring the effects of damage to reward-related striatal systems in combination with fronto-parietal network disruption, even though this is likely to result in altered interactions between motivational and attentional systems (Bourgeois, Chelazzi, & Vuilleumier, 2016).
It has recently been revealed that spatial neglect can be modulated by motivational factors including anticipated monetary reward. A number of dopaminergic agents have been evaluated as treatments for neglect, but the results have been mixed, with no clear anatomical or cognitive predictors of dopaminergic responsiveness. Given that the effects of incentive motivation are mediated by dopaminergic pathways that are variably damaged in stroke, we tested the hypothesis that the modulatory influences of reward and dopaminergic drugs on neglect are themselves related.
We employed a single-dose, double-blind, crossover design to compare the effects of Co-careldopa and placebo on a modified visual cancellation task in patients with neglect secondary to right hemisphere stroke. Whilst confirming that reward improved visual search in this group, we showed that dopaminergic stimulation only enhances visual search in the absence of reward. When patients were divided into REWARD-RESPONDERs and REWARD-NON-RESPONDERs, we found an interaction, such that only REWARD-NON-RESPONDERs showed a positive response to reward after receiving Co-careldopa, whereas REWARD-RESPONDERs were not influenced by drug. At a neuroanatomical level, responsiveness to incentive motivation was most associated with intact dorsal striatum.
These findings suggest that dopaminergic modulation of neglect follows an ‘inverted U’ function, is dependent on integrity of the reward system, and can be measured as a behavioural response to anticipated reward.

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Neglect

Abstract

Neuropsychologia

Neuropsychologia

Cortex

Brain

Brain

Arch Neurol

Brain

J Cogn Neurosci

Effects of Parietal Injury on Covert Orienting of Visual Attention

J Neurosci

How Do the Parietal Lobes Direct Covert Attention?

Neuropsychologia

Selective Spatial Attention in Patients with Visual Extinction

Brain

The Deployment of Visual Attention in the Intact Field of Hemineglect

Cortex

Visual Hemineglect and Hemihallucinations in a Patient with Subcortical Infarction

Neurology

A Cortical Network for Directed Attention and Unilateral Neglect

Ann Neurol

Disappearance of Left-Ward Rapid Eye Movements during Sleep in Hemi-Inattention

Neuroreport

Mental Representation in Unilateral Neglect and Related Disorders: the Twentieth Bartlett Memorial Lecture

Q J Exp Psychol [A]

Orientational Bias Model of Unilateral Neglect: Evidence from Attentional Gradients within Hemispace

Caloric Stimulation and Unilateral Visual Neglect

Neurology

Remission of Hemineglect and Anosognosia after Vestibular Stimulation

Neuropsychologia

Exploring Somatosensory Hemineglect by Vestibular Stimulation

Brain

Remission of Somatoparaphrenic Delusion through Vestibular Stimulation

Neuropsychologia

Effect of Optokinetic Stimulation in Patients with Visual Neglect

Cortex

Components of Visual Attention: Alterations in Response Pattern to Visual Stimuli following Parietal Lobe Infarction

Brain

Parietal Lobe Mechanisms of Spatial Attention: Modality-Specific or Supramodal?

Neuropsychologia

Bimodal Extinction without Cross Modal Extinction

J Neurol Neurosurg Psychiatry

The Anatomical Basis of Spatial Neglect in Humans

Effects of Lesions of the Temporal-Parietal junction on Perceptual and Attentional Processing in Humans

J Neurosci