title: Cerebral correlates of visuospatial neglect: a direct cerebral stimulation study.
abstract: OBJECTIVE
  To assess the role of the superior longitudinal fascicle, the inferior fronto-occipital fascicle, and the posterior parietal lobe in visuospatial attention in humans during awake brain surgery.
  
  
  METHODS
  Seven patients with hemispheric gliomas (six in the right hemisphere) entered the study. During surgery in asleep/awake anesthesia, guided by Diffusion Tensor Imaging Fiber Tractography, visuospatial neglect was assessed during direct electrical stimulation by computerized line bisection.
  
  
  RESULTS
  A rightward deviation, indicating left visuospatial neglect, was induced in six of seven patients by stimulation of the parietofrontal connections, in a location consistent with the trajectory of the second branch of the superior longitudinal fascicle. Stimulation of the medial and dorsal white matter of the superior parietal lobule (corresponding to the first branch of the superior longitudinal fascicle), of the ventral and lateral white matter of the supramarginal gyrus (corresponding to the third branch of the superior longitudinal fascicle), and of the inferior occipitofrontal fasciculus, was largely ineffective. Stimulation of the superior parietal lobule (Brodmann's area 7) caused a marked rightward deviation in all of the six assessed patients, while stimulation of Brodmann's areas 5 and 19 was ineffective.
  
  
  CONCLUSIONS
  The parietofrontal connections of the dorso-lateral fibers of the superior longitudinal fascicle (i.e., the second branch of the fascicle), and the posterior superior parietal lobe (Brodmann's area 7) are involved in the orientation of spatial attention. Spatial neglect should be assessed systematically during awake brain surgery, particularly when the right parietal lobe may be involved by the neurosurgical procedure.
authors: Dipartimento di Psicologia, Università degli Studi di Milano-Bicocca, Piazza dell'Ateneo Nuovo 1, Milano, Italy; Laboratorio di Neuropsicologia, IRCCS Istituto Auxologico Italiano, Milano, Italy.
authors: Giuseppe
authors: G
authors: Vallar
authors: Lorenzo
authors: L
authors: Bello
authors: Emanuela
authors: E
authors: Bricolo
authors: Antonella
authors: A
authors: Castellano
authors: Alessandra
authors: A
authors: Casarotti
authors: Andrea
authors: A
authors: Falini
authors: Marco
authors: M
authors: Riva
authors: Enrica
authors: E
authors: Fava
authors: Costanza
authors: C
authors: Papagno
mesh_terms: D000328:Adult; D000758:Anesthesia; D001932:Brain Neoplasms / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D054022:Cerebrum / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D056324:Diffusion Tensor Imaging; D004558:Electric Stimulation; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D005910:Glioma / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D038361:Neuronavigation; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D010468:Perceptual Disorders / Q000473:pathology / Q000503:physiopathology*; D013028:Space Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D014851:Wakefulness
keywords: cerebral cortex; diffusion tensor imaging; electrical stimulation of the brain; glioma; hemispatial neglect; neuropsychology; neurosurgery; right cerebral hemisphere