Cerebral Cortex Advance Access originally published online on March 26, 2007
Cerebral Cortex 2007 17(12):2914-2932; doi:10.1093/cercor/bhm017
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Representing Spatial Relationships in Posterior Parietal Cortex: Single Neurons Code Object-Referenced Position
1 Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA, 2 Brain Sciences Center, Veterans Affairs Medical Center, Minneapolis, MN 55455, USA, 3 Center for Cognitive Sciences, University of Minnesota, Minneapolis, MN 55455, USA
Address correspondence to Matthew V. Chafee, Brain Sciences Center (11B), Veterans Affairs Medical Center, 1 Veterans Drive, Minneapolis, MN 55417, USA. Email: chafe001{at}umn.edu.
The brain computes spatial relationships as necessary to achieve behavioral goals. Loss of this spatial cognitive ability after damage to posterior parietal cortex may contribute to constructional apraxia, a syndrome in which a patient's ability to reproduce spatial relationships between the parts of an object is disrupted. To explore neural correlates of object-relative spatial representation, we recorded neural activity in parietal area 7a of monkeys performing an object construction task. We found that neurons were activated as a function of the spatial relationship between a task-critical coordinate and a reference object. Individual neurons exhibited an object-relative spatial preference, such that different neural populations were activated when the spatial coordinate was located to the left or right of the reference object. In each case, the representation was robust to translation of the reference object, and neurons maintained their object-relative preference when the position of the object varied relative to the angle of gaze and viewer-centered frames of reference. This provides evidence that the activity of a subpopulation of parietal neurons active in the construction task represented relative position as referenced to an object and not absolute position with respect to the viewer.
Key Words: attention constructional apraxia hemispatial neglect monkey object-centered
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D. A. Crowe, B. B. Averbeck, and M. V. Chafee Neural Ensemble Decoding Reveals a Correlate of Viewer- to Object-Centered Spatial Transformation in Monkey Parietal Cortex J. Neurosci., May 14, 2008; 28(20): 5218 - 5228. [Abstract] [Full Text] [PDF] |
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