What makes written words so special to the brain
Mohamed L Seghier
Reading is an integral part of life in today's information-driven societies. Since the pioneering work of Dejerine on "word blindness" in brain-lesioned patients, the literature has increased exponentially, from neuropsychological case reports to mechanistic accounts of word processing at the behavioural, neurofunctional and computational levels, tapping into diverse aspects of visual word processing. These studies have revealed some exciting findings about visual word processing, including how the brain learns to read, how changes in literacy impact upon word processing strategies, and whether word processing mechanisms vary across different alphabetic, logographic or artificial writing systems. Other studies have attempted to characterise typical and atypical word processes in special populations in order to explain why dyslexic brains struggle with words, how multilingualism changes the way our brains see words, and what the exact developmental signatures are that would shape the acquisition of reading skills. Exciting new insights have also emerged from recent studies that have investigated word stimuli at the system/network level, by looking for instance, at how the reading system interacts with other cognitive systems in a context-dependent fashion, how visual language stimuli are integrated into the speech processing streams, how both left and right hemispheres cooperate and interact during word processing, and what the exact contributions of subcortical and cerebellar regions to reading are. The contributions to this Research Topic highlight the latest findings regarding the different issues mentioned above, particularly how these findings can explain or model the different processes, mechanisms, pathways or cognitive strategies by which the human brain sees words. The introductory editorial, summarising the contributions included here, highlights how varieties of behavioural tests and neuroimaging techniques can be used to investigate word processing mechanisms across different alphabetic and logographic writing systems.