scholarly journals Egocentric representations of space co-exist with allocentric representations: Evidence from spatial neglect

Cortex ◽  
2014 ◽  
Vol 58 ◽  
pp. 161-169 ◽  
Author(s):  
Dongyun Li ◽  
Hans-Otto Karnath ◽  
Christopher Rorden
Keyword(s):  
Spatial Neglect ◽  
Representations Of Space ◽  
Allocentric Representations

scholarly journals Impaired Perceptual Memory of Locations across Gaze-shifts in Patients with Unilateral Spatial Neglect

2007 ◽  
Vol 19 (8) ◽  
pp. 1388-1406 ◽  
Author(s):  
Patrik Vuilleumier ◽  
Claire Sergent ◽  
Sophie Schwartz ◽  
Nathalie Valenza ◽  
Michele Girardi ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Target Location ◽  
Spatial Working Memory ◽  
Memory Deficit ◽  
Spatial Neglect ◽  
Physiological Data ◽  
Right Visual Field ◽  
Gaze Shifts ◽  
Gaze Shift ◽  
Representations Of Space

Right hemisphere lesions often lead to severe disorders in spatial awareness and behavior, such as left hemispatial neglect. Neglect involves not only pathological biases in attention and exploration but also deficits in internal representations of space and spatial working memory. Here we designed a new paradigm to test whether one potential component may involve a failure to maintain an updated representation of visual locations across delays when a gaze-shift intervenes. Right hemisphere patients with varying severity of left spatial neglect had to encode a single target location and retain it across an interval of 2 or 3 sec, during which the target was transiently removed, before a subsequent probe appeared for a same/different location judgment. During the delay, gaze could have to shift to either side of the remembered location, or no gaze-shift was required. Patients showed a dramatic loss of memory for target location after shifting gaze to its right (toward their “intact” ipsilesional side), but not after leftward gaze-shifts. Such impairment arose even when the target initially appeared in the right visual field, before being updated leftward due to right gaze, and even when gaze returned to the screen center before the memory probe was presented. These findings indicate that location information may be permanently degraded when the target has to be remapped leftward in gaze-centric representations. Across patients, the location-memory deficit induced by rightward gaze-shifts correlated with left neglect severity on several clinical tests. This paradoxical memory deficit, with worse performance following gaze-shifts to the “intact” side of space, may reflect losses in gaze-centric representations of space that normally remap a remembered location dynamically relative to current gaze. Right gaze-shifts may remap remembered locations leftward, into damaged representations, whereas left gaze-shifts will require remapping rightward, into intact representations. Our findings accord with physiological data on normal remapping mechanisms in the primate brain but demonstrate for the first time their impact on perceptual spatial memory when damaged, while providing new insights into possible components that may contribute to the neglect syndrome.

Translation Research for the Rehabilitation of Left Spatial Neglect and Associated Disorders of Attention in Stroke Patients

2008 ◽  
Vol 18 (2) ◽  
pp. 55-65 ◽  
Author(s):  
Nkiruka Arene ◽  
Argye E. Hillis
Keyword(s):  
Theoretical Basis ◽  
Attention Bias ◽  
Spatial Neglect ◽  
Clinical Use ◽  
Stroke Patients ◽  
Translation Research ◽  
Unilateral Neglect ◽  
Assessment And Treatment ◽  
Sound Theoretical Basis ◽  
Review Current

Abstract The syndrome of unilateral neglect, typified by a lateralized attention bias and neglect of contralateral space, is an important cause of morbidity and disability after a stroke. In this review, we discuss the challenges that face researchers attempting to elucidate the mechanisms and effectiveness of rehabilitation treatments. The neglect syndrome is a heterogeneous disorder, and it is not clear which of its symptoms cause ongoing disability. We review current methods of neglect assessment and propose logical approaches to selecting treatments, while acknowledging that further study is still needed before some of these approaches can be translated into routine clinical use. We conclude with systems-level suggestions for hypothesis development that would hopefully form a sound theoretical basis for future approaches to the assessment and treatment of neglect.

Transcranial Electrical Stimulation in Post-Stroke Cognitive Rehabilitation

2016 ◽  
Vol 21 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Silvia Convento ◽  
Cristina Russo ◽  
Luca Zigiotto ◽  
Nadia Bolognini
Keyword(s):  
Electrical Stimulation ◽  
Cognitive Rehabilitation ◽  
Cognitive Disorders ◽  
Spatial Neglect ◽  
Transcranial Electrical Stimulation ◽  
Clinical Settings ◽  
Post Stroke ◽  
Neuropsychological Disorders ◽  
Current State ◽  
Stimulation Technique

Abstract. Cognitive rehabilitation is an important area of neurological rehabilitation, which aims at the treatment of cognitive disorders due to acquired brain damage of different etiology, including stroke. Although the importance of cognitive rehabilitation for stroke survivors is well recognized, available cognitive treatments for neuropsychological disorders, such as spatial neglect, hemianopia, apraxia, and working memory, are overall still unsatisfactory. The growing body of evidence supporting the potential of the transcranial Electrical Stimulation (tES) as tool for interacting with neuroplasticity in the human brain, in turn for enhancing perceptual and cognitive functions, has obvious implications for the translation of this noninvasive brain stimulation technique into clinical settings, in particular for the development of tES as adjuvant tool for cognitive rehabilitation. The present review aims at presenting the current state of art concerning the use of tES for the improvement of post-stroke visual and cognitive deficits (except for aphasia and memory disorders), showing the therapeutic promises of this technique and offering some suggestions for the design of future clinical trials. Although this line of research is still in infancy, as compared to the progresses made in the last years in other neurorehabilitation domains, current findings appear very encouraging, supporting the development of tES for the treatment of post-stroke cognitive impairments.

Combining Language and Space: Word Bisection in Unilateral Spatial Neglect

2012 ◽  
Author(s):  
Laura Veronelli ◽  
Giuseppe Vallar ◽  
Chiara V. Marinelli ◽  
Silvia Primativo ◽  
Lisa S. Arduino
Keyword(s):  
Spatial Neglect ◽  
Unilateral Spatial Neglect
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