Electronic versions

  • Kenneth F Valyear
    University of Western Ontario, Canada
  • Jody C Culham
    University of Western Ontario, Canada
  • Nadder Sharif
    McGill University, Montreal, Canada
  • David Westwood
    Dalhousie University, Halifax, Canada
  • Melvyn A Goodale
    University of Western Ontario, Canada

We used an event-related fMR-adaptation paradigm to investigate changes in BOLD activity in the dorsal and ventral visual streams as a function of object identity and object orientation. Participants viewed successive paired images of real-world, graspable objects, separated by a visual mask. The second image of each pair was either: (i) the same as the first image, (ii) different only in identity, (iii) different only in orientation, or (iv) different in both identity and orientation. A region in the parieto-occipital cortex (dorsal stream) showed a selective increase in BOLD activity with changes in object orientation, but was insensitive to changes in object identity. In contrast, a region in the temporo-occipital cortex (ventral stream) showed a selective increase in activity with changes in identity, but was insensitive to changes in orientation. The differential sensitivity to orientation and identity is consistent with the idea that the dorsal stream plays a critical role in the visual control of object-directed actions while the ventral stream plays a critical role in object perception.

Keywords

  • Brain Mapping, Evoked Potentials, Visual, Female, Form Perception, Humans, Magnetic Resonance Imaging, Male, Mental Processes, Occipital Lobe, Orientation, Parietal Lobe, Pattern Recognition, Visual, Reference Values, Saccades, Visual Pathways, Clinical Trial, Comparative Study, Journal Article, Research Support, Non-U.S. Gov't
Original languageEnglish
Pages (from-to)218-28
Number of pages11
JournalNeuropsychologia
Volume44
Issue number2
Early online date13 Jun 2005
DOIs
Publication statusPublished - Feb 2006
Externally publishedYes
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