Anterior regions of monkey parietal cortex process visual 3D shape.
The intraparietal cortex is involved in the control of visually guided actions, like reach-to-grasp movements, which require extracting the 3D shape and position of objects from 2D retinal images. Using fMRI in behaving monkeys, we investigated the role of the intraparietal cortex in processing stereoscopic information for recovering the depth structure and the position in depth of objects. We found that while several areas (CIP, LIP, and AIP on the lateral bank; PIP and MIP on the medial bank) are activated by stereoscopic stimuli, AIP and an adjoining portion of LIP are sensitive only to depth structure. Furthermore, only these two regions are sensitive to both the depth structure and the 2D shape of small objects. These results indicate that extracting 3D spatial information from stereo involves several intraparietal areas, among which AIP and anterior LIP are more specifically engaged in extracting the 3D shape of objects.
Lab Neuro- en Psychofysiologie, K.U. Leuven, Medical School, Campus Gasthuisberg, Herestraat 49, B-3000, Leuven, Belgium.
Jean-Baptiste
JB
Durand
Koen
K
Nelissen
Olivier
O
Joly
Claire
C
Wardak
James T
JT
Todd
J Farley
JF
Norman
Peter
P
Janssen
Wim
W
Vanduffel
Guy A
GA
Orban
D000818:Animals; D001931:Brain Mapping; D003867:Depth Perception / Q000502:physiology*; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging; D008297:Male; D010296:Parietal Lobe / Q000033:anatomy & histology* / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*