Open AccessNew insights into the neural network mediating reading processes provided by cortico‐subcortical electrical mapping
Author(s) -
Zemmoura Ilyess,
Herbet Guillaume,
MoritzGasser Sylvie,
Duffau Hugues
Publication year - 2015
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.22766
Subject(s) - fascicle , white matter , diffusion mri , psychology , neuroscience , optic radiation , temporal lobe , brain mapping , anatomy , magnetic resonance imaging , medicine , epilepsy , radiology
Objectives To ascertain the neural network mediating reading using intraoperative electrostimulation. Experimental design 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. Principal observations 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. Hum Brain Mapp 36:2215–2230, 2015 . © 2015 Wiley Periodicals, Inc.