Open AccessCerebral correlates of visuospatial neglect: A direct cerebral stimulation study
Author(s) -
Vallar Giuseppe,
Bello Lorenzo,
Bricolo Emanuela,
Castellano Antonella,
Casarotti Alessandra,
Falini Andrea,
Riva Marco,
Fava Enrica,
Papagno Costanza
Publication year - 2014
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.22257
Subject(s) - fascicle , superior longitudinal fasciculus , parietal lobe , supramarginal gyrus , white matter , psychology , neuroscience , diffusion mri , anatomy , inferior parietal lobule , occipital lobe , medicine , magnetic resonance imaging , fractional anisotropy , functional magnetic resonance imaging , radiology
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. Experimental design 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. Principal observations 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. Hum Brain Mapp 35:1334–1350, 2014 . © 2013 Wiley Periodicals, Inc.