TY - JOUR T1 - A Distinct Representation of Three-Dimensional Shape in Macaque Anterior Intraparietal Area: Fast, Metric, and Coarse JF - The Journal of Neuroscience JO - J. Neurosci. SP - 10613 LP - 10626 DO - 10.1523/JNEUROSCI.6016-08.2009 VL - 29 IS - 34 AU - Siddharth Srivastava AU - Guy A. Orban AU - Patrick A. De Mazière AU - Peter Janssen Y1 - 2009/08/26 UR - http://www.jneurosci.org/content/29/34/10613.abstract N2 - Differences in the horizontal positions of retinal images—binocular disparity—provide important cues for three-dimensional object recognition and manipulation. We investigated the neural coding of three-dimensional shape defined by disparity in anterior intraparietal (AIP) area. Robust selectivity for disparity-defined slanted and curved surfaces was observed in a high proportion of AIP neurons, emerging at relatively short latencies. The large majority of AIP neurons preserved their three-dimensional shape preference over different positions in depth, a hallmark of higher-order disparity selectivity. Yet both stimulus type (concave–convex) and position in depth could be reliably decoded from the AIP responses. The neural coding of three-dimensional shape was based on first-order (slanted surfaces) and second-order (curved surfaces) disparity selectivity. Many AIP neurons tolerated the presence of disparity discontinuities in the stimulus, but the population of AIP neurons provided reliable information on the degree of curvedness of the stimulus. Finally, AIP neurons preserved their three-dimensional shape preference over different positions in the frontoparallel plane. Thus, AIP neurons extract or have access to three-dimensional object information defined by binocular disparity, consistent with previous functional magnetic resonance imaging data. Unlike the known representation of three-dimensional shape in inferior temporal cortex, the neural representation in AIP appears to emphasize object parameters required for the planning of grasping movements. ER -