title: The neural correlates of object-centered processing in reading: a lesion study of neglect dyslexia.
abstract: Neglect dyslexia--a peripheral reading disorder generally associated with left spatial neglect--is characterized by omissions or substitutions of the initial letters of words. Several observations suggest that neglect dyslexia errors are independent of viewer-centered coordinates; the disorder is therefore thought to reflect impairment at the level of object-centered representations. This hypothesis is indirectly supported by lesion studies connecting object-centered neglect errors with damage to posterior cortical regions lying in the ventral visual stream. Here, we performed a lesion-symptom mapping study of 40 patients with spatial neglect asked to read words presented at different positions relative to a viewer-centered coordinate frame. We found that the frequency of object-centered reading errors was constant across horizontal positions, whereas the frequency of entirely neglected words (reflecting a page-centered deficit) linearly increased from right to left. Damage to the intraparietal sulcus and the angular and middle temporal gyri was the best predictor of object-centered errors. We discuss these findings with reference to a role of the posterior parietal lobe in adapting the size of the attentional focus and biasing object representations elaborated in the ventral visual stream.
authors: Division of Neurorehabilitation, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland. radek.ptak@hcuge.ch
authors: Radek
authors: R
authors: Ptak
authors: Marie
authors: M
authors: Di Pietro
authors: Armin
authors: A
authors: Schnider
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology*; D004410:Dyslexia / Q000150:complications / Q000473:pathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000150:complications / Q000473:pathology*; D010775:Photic Stimulation; D011932:Reading; D014825:Vocabulary