title: Right Cortical and Axonal Structures Eliciting Ocular Deviation During Electrical Stimulation Mapping in Awake Patients.
abstract: To investigate the neural network underpinning eye movements, a cortical and subcortical intraoperative mapping using direct electrical stimulation (DES) was achieved in six awake patients during surgery for a right frontal low-grade glioma. We assessed the relationship between the occurrence of ocular deviation during both cortical and axonal DES and the anatomic location for each response. The corresponding stimulation sites were reported on a standard brain template for visual analysis and between-subjects comparisons. Our results showed that DES of the cortical frontal eye field (FEF) elicited horizontal (anterior FEF) or upward (posterior FEF) eye movements in 3 patients, supporting the fact that FEF comprises several distinct functional subregions. In addition, subcortical stimulation of the white matter tracts underneath the FEF evoked conjugate contraversive ocular deviation in 3 other patients. Interestingly, this region seems to be a crossroad between the fronto-striatal tract, the frontal aslant tract, the inferior fronto-occipital fascicle and the superior longitudinal fascicle. No deficits in eye movements were observed following surgery. To our knowledge, this is the first study reporting ocular deviation during axonal electrostimulation mapping of the white matter fibers in awake patients. Therefore, our original data issued from DES give new insights into the cortical and subcortical structures involved in the control of eye movements and their strong relationships with other functional pathways.
authors.affiliation: Department of Neurosurgery, Azienda Ospedaliera Universitaria Pisana, University of Pisa, Pisa, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Montemurro
authors.affiliation: Department of Neurosurgery, Gui de Chauliac Hospital, Montpellier University Medical Center, 80 Avenue Augustin Fliche, 34295, Montpellier, France.|Team "Plasticity of Central Nervous System, Stem Cells and Glial Tumors,", INSERM U1051, Institute for Neurosciences of Montpellier, Montpellier, France.|University of Montpellier, Montpellier, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Herbet
authors.affiliation: Department of Neurosurgery, Gui de Chauliac Hospital, Montpellier University Medical Center, 80 Avenue Augustin Fliche, 34295, Montpellier, France. h-duffau@chu-montpellier.fr.|Team "Plasticity of Central Nervous System, Stem Cells and Glial Tumors,", INSERM U1051, Institute for Neurosciences of Montpellier, Montpellier, France. h-duffau@chu-montpellier.fr.
authors.forename: Hugues
authors.initials: H
authors.lastname: Duffau
mesh_terms: D000328:Adult; D001369:Axons / Q000502:physiology*; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000601:surgery; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D004558:Electric Stimulation; D005133:Eye Movements; D005260:Female; D005910:Glioma / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net; D014851:Wakefulness
keywords: Direct electrical stimulation; Eye movements; Frontal eye field; Ocular deviation; White matter tracts