title: Cross-modal activation of visual cortex during depth perception using auditory substitution of vision.
abstract: Previous neuroimaging studies identified multimodal brain areas in the visual cortex that are specialized for processing specific information, such as visual-haptic object recognition. Here, we test whether visual brain areas are involved in depth perception when auditory substitution of vision is used. Nine sighted volunteers were trained blindfolded to use a prosthesis substituting vision with audition both to recognize two-dimensional figures and to estimate distance of an object in a real three-dimensional environment. Using positron emission tomography, regional cerebral blood flow was assessed while the prosthesis was used to explore virtual 3D images; subjects focused either on 2D features (target search) or on depth (target distance comparison). Activation foci were found in visual association areas during both the target search task, which recruited the occipito-parietal cortex, and the depth perception task, which recruited occipito-parietal and occipito-temporal areas. This indicates that some brain areas of the visual cortex are relatively multimodal and may be recruited for depth processing via a sense other than vision.
authors.affiliation: Neural Rehabilitation Engineering Laboratory, Université Catholique de Louvain, Av Hippocrate, Brussels, Belgium.
authors.forename: Laurent
authors.initials: L
authors.lastname: Renier
authors.forename: Olivier
authors.initials: O
authors.lastname: Collignon
authors.forename: Colline
authors.initials: C
authors.lastname: Poirier
authors.forename: Dai
authors.initials: D
authors.lastname: Tranduy
authors.forename: Annick
authors.initials: A
authors.lastname: Vanlierde
authors.forename: Anne
authors.initials: A
authors.lastname: Bol
authors.forename: Claude
authors.initials: C
authors.lastname: Veraart
authors.forename: Anne G
authors.initials: AG
authors.lastname: De Volder
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D002560:Cerebrovascular Circulation; D003627:Data Interpretation, Statistical; D003867:Depth Perception / Q000502:physiology*; D005556:Form Perception / Q000502:physiology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D009415:Nerve Net / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D049268:Positron-Emission Tomography; D019736:Prostheses and Implants; D011597:Psychomotor Performance / Q000502:physiology; D011999:Recruitment, Neurophysiological / Q000502:physiology; D012858:Size Perception / Q000502:physiology; D014793:Visual Cortex / Q000000981:diagnostic imaging / Q000502:physiology*