TY - JOUR
T1 - Control of hand shaping in response to object shape perturbation
AU - Ansuini, Caterina
AU - Santello, Marco
AU - Tubaldi, Federico
AU - Massaccesi, Stefano
AU - Castiello, Umberto
N1 - Funding Information:
Acknowledgments This work was supported by a grant from the Ministry of Education and Research to UC. We would like to thank Gianmarco Altoè for statistical advice.
PY - 2007/6
Y1 - 2007/6
N2 - This study assessed how hand shaping responds to a perturbation of object shape. In blocked trials (80% of total), subjects were instructed to reach, to grasp and lift a concave or a convex object. In perturbed trials (20% of total), a rotating device allowed for the rapid change from the concave to the convex object or vice versa. In this situation subjects grasped the last presented object. Flexion/extension at the metacarpal-phalangeal and proximal interphalangeal joints of all digits was measured by resistive sensors embedded in a glove. In the blocked condition we found that most joints of the fingers were modulated by the type of the to-be-grasped object during the reach. When object shape was perturbed, reach duration was longer and angular excursion of all fingers differed with respect to blocked trials. For the 'convex → concave' perturbation, a greater degree of finger extension was found than during the blocked 'concave' trials. In contrast, for the 'concave → convex' perturbation, fingers were more flexed than for the blocked 'convex' trials. The thumb reacted to the perturbation showing a similar pattern (i.e., over-flexion with respect to the blocked trials) regardless the 'direction' of the perturbation. The present results suggest that applying an object shape perturbation during a reach-to-grasp action determines a reorganization of all digits. This pattern is suggestive of a control strategy, which assigns to opposing digits different roles.
AB - This study assessed how hand shaping responds to a perturbation of object shape. In blocked trials (80% of total), subjects were instructed to reach, to grasp and lift a concave or a convex object. In perturbed trials (20% of total), a rotating device allowed for the rapid change from the concave to the convex object or vice versa. In this situation subjects grasped the last presented object. Flexion/extension at the metacarpal-phalangeal and proximal interphalangeal joints of all digits was measured by resistive sensors embedded in a glove. In the blocked condition we found that most joints of the fingers were modulated by the type of the to-be-grasped object during the reach. When object shape was perturbed, reach duration was longer and angular excursion of all fingers differed with respect to blocked trials. For the 'convex → concave' perturbation, a greater degree of finger extension was found than during the blocked 'concave' trials. In contrast, for the 'concave → convex' perturbation, fingers were more flexed than for the blocked 'convex' trials. The thumb reacted to the perturbation showing a similar pattern (i.e., over-flexion with respect to the blocked trials) regardless the 'direction' of the perturbation. The present results suggest that applying an object shape perturbation during a reach-to-grasp action determines a reorganization of all digits. This pattern is suggestive of a control strategy, which assigns to opposing digits different roles.
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U2 - 10.1007/s00221-006-0840-9
DO - 10.1007/s00221-006-0840-9
M3 - Article
C2 - 17256167
AN - SCOPUS:34249870591
SN - 0014-4819
VL - 180
SP - 85
EP - 96
JO - Experimental Brain Research
JF - Experimental Brain Research
IS - 1
ER -