title: Association of dorsal inferior frontooccipital fasciculus fibers in the deep parietal lobe with both reading and writing processes: a brain mapping study.
abstract: Alexia and agraphia are disorders common to the left inferior parietal lobule, including the angular and supramarginal gyri. However, it is still unclear how these cortical regions interact with other cortical sites and what the most important white matter tracts are in relation to reading and writing processes. Here, the authors present the case of a patient who underwent an awake craniotomy for a left inferior parietal lobule glioma using direct cortical and subcortical electrostimulation. The use of subcortical stimulation allowed identification of the specific white matter tracts associated with reading and writing. These tracts were found as portions of the dorsal inferior frontooccipital fasciculus (IFOF) fibers in the deep parietal lobe that are responsible for connecting the frontal lobe to the superior parietal lobule. These findings are consistent with previous diffusion tensor imaging tractography and functional MRI studies, which suggest that the IFOF may play a role in the reading and writing processes. This is the first report of transient alexia and agraphia elicited through intraoperative direct subcortical electrostimulation, and the findings support the crucial role of the IFOF in reading and writing.
authors.affiliation: Department of Neurosurgery and.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Motomura
authors.forename: Masazumi
authors.initials: M
authors.lastname: Fujii
authors.forename: Satoshi
authors.initials: S
authors.lastname: Maesawa
authors.forename: Shunichiro
authors.initials: S
authors.lastname: Kuramitsu
authors.forename: Atsushi
authors.initials: A
authors.lastname: Natsume
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Wakabayashi
mesh_terms: D001931:Brain Mapping; D001932:Brain Neoplasms / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D003399:Craniotomy; D056324:Diffusion Tensor Imaging; D005910:Glioma / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology / Q000502:physiology*; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology*; D010296:Parietal Lobe / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D011932:Reading; D014956:Writing
keywords: AF = arcuate fasciculus; DTI = diffusion tensor imaging; IFOF = inferior frontooccipital fasciculus; ILF = inferior longitudinal fasciculus; MET = l-[methyl-11C]methionine; ROI = region of interest; SLF = superior longitudinal fasciculus; SLTA = Standard Language Test of Aphasia; VWFA = visual word form area; WAIS-III = Wechsler Adult Intelligence Scale, 3rd edition; WMS-R = Wechsler Memory Scale–Revised; brain mapping; fMRI = functional MRI; functional neurosurgery; inferior frontooccipital fasciculus; reading; subcortical stimulation; writing