title: Is the human left middle longitudinal fascicle essential for language? A brain electrostimulation study.
abstract: Human brain pathways required for language processing are poorly known. A new white matter tract in humans, the middle longitudinal fascicle, has recently been anatomically determined by diffusion tensor imaging and suggested to be essential for language. Our aim is to determine the importance of the middle longitudinal fascicle for language processing. This study is based on 8 patients with glioma resection at least involving the superior temporal gyrus of the left dominant hemisphere. Language is systematically examined pre- and postoperatively at 3 months. Intraoperative electrostimulation is used to map cortical and subcortical structures as functional boundaries of the glioma resection, including those essential for language processing. The resections are extensive (on average 62 ml, ranging from 21 to 111 ml) and include a large part of the middle longitudinal fascicle in all patients. Intraoperatively, no interference with picture naming is observed by electrostimulation of the middle longitudinal fascicle, while in all patients the inferior fronto-occipital fascicle is identified by eliciting semantic paraphasia as functional boundary. Postoperatively, no new permanent language deficits are detected by systematic language examination. Therefore, we suggest that the middle longitudinal fascicle may participate but is not essential for language processing.
authors.affiliation: Neurosurgical Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Philip C
authors.initials: PC
authors.lastname: De Witt Hamer
authors.forename: Sylvie
authors.initials: S
authors.lastname: Moritz-Gasser
authors.forename: Peggy
authors.initials: P
authors.lastname: Gatignol
authors.forename: Hugues
authors.initials: H
authors.lastname: Duffau
mesh_terms: D000328:Adult; D001037:Aphasia / Q000503:physiopathology; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000601:surgery; D005260:Female; D007839:Functional Laterality; D005910:Glioma / Q000601:surgery; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000502:physiology*