RT Journal Article
SR Electronic
T1 Invariant characteristics of a pointing movement in man
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 710
OP 720
DO 10.1523/JNEUROSCI.01-07-00710.1981
VO 1
IS 7
A1 JF Soechting
A1 F Lacquaniti
YR 1981
UL http://www.jneurosci.org/content/1/7/710.abstract
AB Simple arm movements involving forward projection of the hand toward a target were studied by measuring simultaneous wrist position in three- dimensional space and changes in elbow angle. An attempt was made to identify those features of the movement which exhibit invariant characteristics under the hypothesis that such invariances may reflect the operations by which central processes participate in the organization of the movement. The first such invariance to be identified was that the trajectory in space is independent of movement speed. Secondly, the movement can be viewed as consisting of two phases, an acceleratory phase and a deceleratory one, with the movement during the acceleratory phase being so organized as to maintain the ratio of elbow angular velocity to shoulder angular velocity invariant with respect to target location in the deceleratory phase. It is suggested that proprioceptive information is used to control the movement and that the latter invariance may result from a negative feedback of force involving tendon organ afferents.