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Prism adaptation enhances activity of intact fronto-parietal areas in both hemispheres in neglect patients

Publié dansCortex, vol. 49, no. 1, p. 107-119
Date de publication2013
Résumé

Unilateral spatial neglect involves a failure to report or orient to stimuli in the contralesional (left) space due to right brain damage, with severe handicap in everyday activities and poor rehabilitation outcome. Because behavioral studies suggest that prism adaptation may reduce spatial neglect, we investigated the neural mechanisms underlying prism effects on visuo-spatial processing in neglect patients. We used functional magnetic resonance imaging (fMRI) to examine the effect of (right-deviating) prisms on seven patients with left neglect, by comparing brain activity while they performed three different spatial tasks on the same visual stimuli (bisection, search, and memory), before and after a single prism-adaptation session. Following prism adaptation, fMRI data showed increased activation in bilateral parietal, frontal, and occipital cortex during bisection and visual search, but not during the memory task. These increases were associated with significant behavioral improvement in the same two tasks. Changes in neural activity and behavior were seen only after prism adaptation, but not attributable to mere task repetition. These results show for the first time the neural substrates underlying the therapeutic benefits of prism adaptation, and demonstrate that visuo-motor adaptation induced by prism exposure can restore activation in bilateral brain networks controlling spatial attention and awareness. This bilateral recruitment of fronto-parietal networks may counteract the pathological biases produced by unilateral right hemisphere damage, consistent with recent proposals that neglect may reflect lateralized deficits induced by bilateral hemispheric dysfunction.

Mots-clés
  • Adaptation, Physiological/physiology
  • Adult
  • Aged
  • Aged, 80 and over
  • Attention/physiology
  • Brain Mapping
  • Female
  • Frontal Lobe/physiopathology
  • Functional Laterality/physiology
  • Humans
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Nerve Net/physiopathology
  • Neuropsychological Tests
  • Parietal Lobe/physiopathology
  • Perceptual Disorders/physiopathology/rehabilitation
  • Photic Stimulation
  • Visual Perception/physiology
Citation (format ISO)
SAJ, Arnaud et al. Prism adaptation enhances activity of intact fronto-parietal areas in both hemispheres in neglect patients. In: Cortex, 2013, vol. 49, n° 1, p. 107–119. doi: 10.1016/j.cortex.2011.10.009
Fichiers principaux (1)
Article (Published version)
accessLevelRestricted
Identifiants
ISSN du journal0010-9452
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Création22/11/2013 09:38:00
Première validation22/11/2013 09:38:00
Heure de mise à jour14/03/2023 20:57:06
Changement de statut14/03/2023 20:57:06
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