title: Top-down modulations from dorsal stream in lexical recognition: an effective connectivity FMRI study.
abstract: Both the ventral and dorsal visual streams in the human brain are known to be involved in reading. However, the interaction of these two pathways and their responses to different cognitive demands remains unclear. In this study, activation of neural pathways during Chinese character reading was acquired by using a functional magnetic resonance imaging (fMRI) technique. Visual-spatial analysis (mediated by the dorsal pathway) was disassociated from lexical recognition (mediated by the ventral pathway) via a spatial-based lexical decision task and effective connectivity analysis. Connectivity results revealed that, during spatial processing, the left superior parietal lobule (SPL) positively modulated the left fusiform gyrus (FG), while during lexical processing, the left SPL received positive modulatory input from the left inferior frontal gyrus (IFG) and sent negative modulatory output to the left FG. These findings suggest that the dorsal stream is highly involved in lexical recognition and acts as a top-down modulator for lexical processing.
authors.affiliation: Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Science, Beijing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Deng
authors.forename: Ruifang
authors.initials: R
authors.lastname: Guo
authors.forename: Guosheng
authors.initials: G
authors.lastname: Ding
authors.forename: Danling
authors.initials: D
authors.lastname: Peng
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology; D010775:Photic Stimulation; D011932:Reading; D021641:Recognition, Psychology / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*