Cerebral Cortex December 2003; 13:1313-1333
© Oxford University Press 2003
Visual Word Recognition in the Left and Right Hemispheres: Anatomical and Functional Correlates of Peripheral Alexias
1 Institut de Neurologie, Hôpital de la Salpêtrière, AP-HP, Paris, France, 2 INSERM U562, Service Hospitalier Frédéric Joliot, CEA/DSV, Orsay, France, 3 IFR 49 (Institut d’Imagerie Neurofonctionnelle), France, 4 Service de Neuroradiologie Fischgold, Hôpital de la Salpêtrière, AP-HP, Paris, France, 5 Service des Urgences Cérébro-Vasculaires, Hôpital de la Salpêtrière, AP-HP, Paris, France, 6 Centre d’Anatomie Cognitive, Hôpital de la Salpêtrière, AP-HP, Paris, France
According to a simple anatomical and functional model of word reading, letters displayed in one hemifield are first analysed through a cascade of contralateral retinotopic areas, which compute increasingly abstract representations. Eventually, an invariant representation of letter identities is created in the visual word form area (VWFA), reproducibly located within the left occipito-temporal sulcus. The VWFA then projects to structures involved in phonological or lexico-semantic processing. This model yields detailed predictions on the reading impairments that may follow left occipitotemporal lesions. Those predictions were confronted to behavioural, anatomical and functional MRI data gathered in normals and in patients suffering from left posterior cerebral artery infarcts. In normal subjects, alphabetic stimuli activated both the VWFA and the right-hemispheric symmetrical region (R-VWFA) relative to fixation, but only the VWFA showed a preference for alphabetic strings over simple chequerboards. The comparison of normalized brain lesions with reading-induced activations showed that the critical lesion site for the classical syndrome of pure alexia can be tightly localized to the VWFA. Reading impairments resulting from deafferentation of an intact VWFA from right- or left-hemispheric input were dissected using the same methods, shedding light on the connectivity of the VWFA. Finally, the putative role of right-hemispheric processing in the letter-by-letter reading strategy was clarified. In a letter-by-letter reader, the R-VWFA assumed some of the functional properties normally specific to the VWFA. These data corroborate our initial model of normal word perception and underline that an alternative right-hemispheric pathway can underlie functional recovery from alexia.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  C. Corradi-Dell'Acqua, M. D. Hesse, R. I. Rumiati, and G. R. Fink Where is a Nose with Respect to a Foot? The Left Posterior Parietal Cortex Processes Spatial Relationships among Body Parts Cereb Cortex, April 18, 2008; (2008) bhn046v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Xue and R. A. Poldrack The neural substrates of visual perceptual learning of words: implications for the visual word form area hypothesis. J. Cogn. Neurosci., October 1, 2007; 19(10): 1643 - 1655. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. E. Hillis Aphasia: Progress in the last quarter of a century Neurology, July 10, 2007; 69(2): 200 - 213. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Pobric, S. R. Schweinberger, and M. Lavidor Magnetic stimulation of the right visual cortex impairs form-specific priming. J. Cogn. Neurosci., June 1, 2007; 19(6): 1013 - 1020. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Vinckier, L. Naccache, C. Papeix, J. Forget, V. Hahn-Barma, S. Dehaene, and L. Cohen "What" and "Where" in Word Reading: Ventral Coding of Written Words Revealed by Parietal Atrophy J. Cogn. Neurosci., December 1, 2006; 18(12): 1998 - 2012. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Fiset, F. Gosselin, C. Blais, and M. Arguin Inducing Letter-by-letter Dyslexia in Normal Readers. J. Cogn. Neurosci., September 1, 2006; 18(9): 1466 - 1476. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A P Leff, G Spitsyna, G T Plant, and R J S Wise Structural anatomy of pure and hemianopic alexia J. Neurol. Neurosurg. Psychiatry, September 1, 2006; 77(9): 1004 - 1007. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Shin, M. Fabiani, and G. Gratton Multiple levels of stimulus representation in visual working memory. J. Cogn. Neurosci., May 1, 2006; 18(5): 844 - 858. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. E. HILLIS Brain/Language Relationships Identified with Diffusion and Perfusion MRI: Clinical Applications in Neurology and Neurosurgery Ann. N.Y. Acad. Sci., December 1, 2005; 1064(1): 149 - 161. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. Maurer, S. Brem, K. Bucher, and D. Brandeis Emerging Neurophysiological Specialization for Letter Strings J. Cogn. Neurosci., October 1, 2005; 17(10): 1532. [Abstract] [Full Text] [PDF]
|
|