Document Detail

Coordinate transformations for hand-guided saccades.
MedLine Citation:
PMID:  19404624     Owner:  NLM     Status:  MEDLINE    
Relatively little is known about the role of proprioception in eye-hand coordination. In a previous article (Ren et al. J Neurophysiol 96:1464-1477, 2006), we observed anisotropic (direction-dependent) saccade overshoots to hand-held targets during active, but not passive hand movements. We hypothesized that these errors arose from a limb-centered anisotropic efference copy which was transformed (uncompensated) into head coordinates for saccade control. Here, we tested this hypothesis and the role of head orientation signals in this transformation, by dissociating limb coordinates from head coordinates. Twelve human subjects made saccades to hand-held targets actively placed at eight radial locations on a frontally placed table in a dark room with four conditions: (1) right hand (body and head centered), (2) left hand (body and head centered), (3) right hand (head tilted counter-clockwise), (4) right hand (head tilted clockwise). In condition 1, we observed the same anisotropic pattern of overshooting errors-approximately along the axis of the forearm-that we reported previously. Overall, these amplitude errors were much smaller for the left hand. However, the anisotropic pattern was observed for both hands, but reversed symmetrically between the right versus left hand. Head tilt did not cause any systematic errors in saccade direction. Moreover, during head tilt, the anisotropic amplitude errors-while showing some distortions-did not rotate with the head. These findings suggest that transformations of somatosensory information into oculomotor coordinates account for head orientation, and that the anisotropic amplitude errors in hand-guided saccades arise in limb coordinates.
L Ren; J D Crawford
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-04-30
Journal Detail:
Title:  Experimental brain research     Volume:  195     ISSN:  1432-1106     ISO Abbreviation:  Exp Brain Res     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-05-08     Completed Date:  2009-08-11     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  455-65     Citation Subset:  IM    
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MeSH Terms
Motor Skills*
Task Performance and Analysis
Young Adult

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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