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Neuropsychologia 44 (2006) 25942606 The posterior parietal cortex: Sensorimotor interface for the

Summary: Neuropsychologia 44 (2006) 2594­2606
The posterior parietal cortex: Sensorimotor interface for the
planning and online control of visually guided movements
Christopher A. Buneoa,, Richard A. Andersenb
a Harrington Department of Bioengineering, Arizona State University, P.O. Box 879709, Tempe, AZ 85287-9709, USA
b Division of Biology, California Institute of Technology, Mail Code 216-76, Pasadena, CA 91125, USA
Received 14 June 2005; received in revised form 15 September 2005; accepted 11 October 2005
Available online 21 November 2005
We present a view of the posterior parietal cortex (PPC) as a sensorimotor interface for visually guided movements. Special attention is given
to the role of the PPC in arm movement planning, where representations of target position and current hand position in an eye-centered frame
of reference appear to be mapped directly to a representation of motor error in a hand-centered frame of reference. This mapping is direct in
the sense that it does not require target position to be transformed into intermediate reference frames in order to derive a motor error signal in
hand-centered coordinates. Despite being direct, this transformation appears to manifest in the PPC as a gradual change in the functional properties
of cells along the ventro­dorsal axis of the superior parietal lobule (SPL), i.e. from deep in the sulcus to the cortical surface. Possible roles for the
PPC in context dependent coordinate transformations, formation of intrinsic movement representations, and in online control of visually guided
arm movements are also discussed. Overall these studies point to the emerging view that, for arm movements, the PPC plays a role not only in
the inverse transformations required to convert sensory information into motor commands but also in `forward' transformations as well, i.e. in
integrating sensory input with previous and ongoing motor commands to maintain a continuous estimate of arm state that can be used to update
present and future movement plans. Critically, this state estimate appears to be encoded in an eye-centered frame of reference.


Source: Andersen, Richard - Division of Biology, California Institute of Technology


Collections: Biology and Medicine