title: Normal form from biological motion despite impaired ventral stream function.
abstract: We explored the extent to which biological motion perception depends on ventral stream integration by studying LG, an unusual case of developmental visual agnosia. LG has significant ventral stream processing deficits but no discernable structural cortical abnormality. LG's intermediate visual areas and object-sensitive regions exhibit abnormal activation during visual object perception, in contrast to area V5/MT+ which responds normally to visual motion (Gilaie-Dotan, Perry, Bonneh, Malach, & Bentin, 2009). Here, in three studies we used point light displays, which require visual integration, in adaptive threshold experiments to examine LG's ability to detect form from biological and non-biological motion cues. LG's ability to detect and discriminate form from biological motion was similar to healthy controls. In contrast, he was significantly deficient in processing form from non-biological motion. Thus, LG can rely on biological motion cues to perceive human forms, but is considerably impaired in extracting form from non-biological motion. Finally, we found that while LG viewed biological motion, activity in a network of brain regions associated with processing biological motion was functionally correlated with his V5/MT+ activity, indicating that normal inputs from V5/MT+ might suffice to activate his action perception system. These results indicate that processing of biologically moving form can dissociate from other form processing in the ventral pathway. Furthermore, the present results indicate that integrative ventral stream processing is necessary for uncompromised processing of non-biological form from motion.
authors.affiliation: Institute of Cognitive Neuroscience, University College London, London, UK; Wellcome Trust Centre for Neuroimaging, University College London, London, UK. Electronic address: shagido@gmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Gilaie-Dotan
authors.affiliation: Department of Psychology, Hebrew University of Jerusalem, Jerusalem, Israel; Interdisciplinary Center for Neural Computation, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: S
authors.initials: S
authors.lastname: Bentin
authors.affiliation: Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Harel
authors.affiliation: Institute of Cognitive Neuroscience, University College London, London, UK; Wellcome Trust Centre for Neuroimaging, University College London, London, UK.
authors.forename: G
authors.initials: G
authors.lastname: Rees
authors.affiliation: Department of Cognitive Science and Neuroscience Program, University of California San Diego, 9500 Gilman Drive, San Diego, CA 92093-0515, USA. Electronic address: saygin@cogsci.ucsd.edu.
authors.forename: A P
authors.initials: AP
authors.lastname: Saygin
mesh_terms: D000328:Adult; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010468:Perceptual Disorders / Q000503:physiopathology*; D010775:Photic Stimulation; D021641:Recognition, Psychology; D014793:Visual Cortex / Q000098:blood supply / Q000503:physiopathology; D014795:Visual Pathways / Q000098:blood supply / Q000503:physiopathology; D055815:Young Adult
chemical_list: D010100:Oxygen