| Sensory-spatial transformations in the left posterior parietal cortex may contribute to reach timing. | |
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MedLine Citation:
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PMID: 20810686 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The posterior parietal cortex (PPC) contains viewer-centered spatial maps important for reaching movements. It is known that spatial reaching deficits emerge when this region is damaged, yet less is known about temporal deficits that may also emerge because of a failure in sensory-spatial transformations. This work introduces a new geometric measure to quantify multimodal sensory transformation and integration deficits affecting the tempo of reaching trajectories that are induced by injury to the left PPC. Erratic rates of positional change involving faulty maps from rotational angular displacements to translational linear displacements contributed to temporal abnormalities in the reach. Such disruptions were quantified with a time-invariant geometric measure. This measure, paired with an experimental paradigm that manipulated the source of visual guidance for reaches, was used to compare the performance of normal controls to those from a patient (T.R.) who had a lesion in his left-PPC. For controls, the source of visual guidance significantly scaled the tempo of target-directed reaches but did not change the geometric measure. This was not the case in patient T.R., who altered this measure. With continuous, extrapersonal visual feedback of the target, however, these abnormalities improved. Vision of the target rather than vision of his moving hand also improved his arm-joint rotations for posture control. These results show that the left PPC is critically important for visuo-motor transformations that specifically rely on extrapersonal cues to align rotational-arm and linear-hand displacements and to continuously integrate their rates of change. The intactness of this system contributes to the fluidity of the reach's tempo. |
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Authors:
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Elizabeth B Torres; Anastasia Raymer; Leslie J Gonzalez Rothi; Kenneth M Heilman; Howard Poizner |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S. Date: 2010-09-01 |
Journal Detail:
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Title: Journal of neurophysiology Volume: 104 ISSN: 1522-1598 ISO Abbreviation: J. Neurophysiol. Publication Date: 2010 Nov |
Date Detail:
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Created Date: 2010-11-03 Completed Date: 2011-02-11 Revised Date: 2011-11-01 |
Medline Journal Info:
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Nlm Unique ID: 0375404 Medline TA: J Neurophysiol Country: United States |
Other Details:
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Languages: eng Pagination: 2375-88 Citation Subset: IM |
Affiliation:
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Psychology Department, Rutgers University, Piscataway, NJ 08854, USA. ebtorres@rci.rutgers.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Analysis of Variance Humans Magnetic Field Therapy Middle Aged Motor Activity / physiology* Parietal Lobe / physiology* Psychomotor Performance / physiology* Space Perception / physiology |
| Grant Support | |
ID/Acronym/Agency:
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2 R01 NS-036449/NS/NINDS NIH HHS; R01 NS036449-12/NS/NINDS NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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