title: New insights into the neural network mediating reading processes provided by cortico-subcortical electrical mapping.
abstract: OBJECTIVE
  To ascertain the neural network mediating reading using intraoperative electrostimulation.
  
  
  METHODS
  A cortical and axonal intraoperative electrical mapping of reading processes was achieved in seven patients who underwent awake surgery for a left occipitotemporal glioma. We performed resection cavity overlapping and superimposition with a diffusion tensor imaging-based white matter atlas. We assessed the relationship between the location of resection cavities and the occurrence of reading impairments of regular, irregular, and pseudowords.
  
  
  RESULTS
  Intraoperative stimulation of the left posterior inferior temporal cortex (ITCp) elicited reading disturbances. Subcortical stimulation at the anterior portion of the visual word form area (VWFA) induced addressed phonology (irregular words reading) disturbances. Subcortical stimulation of the connection between VWFA and the posterior segment of the arcuate fascicle (AFp) induced both addressed and assembled phonology (irregular and pseudowords reading) disturbances. Postoperative assessment showed that resection of the posterior portion of the inferior longitudinal fascicle (ILFp), connecting the visual cortex to VWFA, induced long-term and global reading impairment. Resection of the terminations of left AFp in the ITCp-induced irregular and pseudowords reading disturbances with no impairment of regular words reading. Resection of the anterior portion of ILF did not induce reading impairment.
  
  
  CONCLUSIONS
  Our data support an inner posterior-to-anterior hierarchical coding of letter strings in the VWFA and a crucial role of the left ILFp to provide visual inputs to the VWFA. Furthermore, we suggest that the AFp is involved in an interactive feedback system between visual and nonvisual information, recruited when reading irregular and pseudowords.
authors: Department of Neurosurgery, Université François-Rabelais de Tours, Inserm, Imagerie et Cerveau UMR U930, Tours, France; CHRU de Tours, Service de Neurochirurgie, Tours, France.
authors: Ilyess
authors: I
authors: Zemmoura
authors: Guillaume
authors: G
authors: Herbet
authors: Sylvie
authors: S
authors: Moritz-Gasser
authors: Hugues
authors: H
authors: Duffau
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology* / Q000601:surgery; D001931:Brain Mapping / Q000379:methods; D001932:Brain Neoplasms / Q000503:physiopathology / Q000601:surgery; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005910:Glioma / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology; D011932:Reading; D055815:Young Adult
keywords: awake surgery; connectivity; inferior longitudinal fascicle; reading; subcortical electrostimulation; superior longitudinal fascicle; visual word form area