RT Journal Article
SR Electronic
T1 Anticipatory Control of Grasping: Independence of Sensorimotor Memories for Kinematics and Kinetics
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 12765
OP 12774
DO 10.1523/JNEUROSCI.4335-08.2008
VO 28
IS 48
A1 Jamie R. Lukos
A1 Caterina Ansuini
A1 Marco Santello
YR 2008
UL http://www.jneurosci.org/content/28/48/12765.abstract
AB We have recently provided evidence for anticipatory grasp control mechanisms in the kinematic domain by showing that subjects modulate digit placement on an object based on its center of mass (CM) when it can be anticipated (Lukos et al., 2007). This behavior relied on sensorimotor memories about digit contact points and forces required for optimal manipulation. We found that accurate sensorimotor memories depended on the acquisition of implicit knowledge about object properties associated with repeated manipulations of the same object. Whereas implicit knowledge of object properties is essential for anticipatory grasp control, the extent to which subjects can use explicit knowledge to accurately scale digit forces in an anticipatory manner is controversial. Additionally, it is not known whether subjects are able to use explicit knowledge of object properties for anticipatory control of contact points. We addressed this question by asking subjects to grasp and lift an object while providing explicit knowledge of object CM location as visual or verbal cues. Contact point modulation and object roll, a measure of anticipatory force control, were assessed using blocked and random CM presentations. We found that explicit knowledge of object CM enabled subjects to modulate contact points. In contrast, subjects could not minimize object roll in the random condition to the same extent as in the blocked when provided with a verbal or visual cue. These findings point to a dissociation in the effect of explicit knowledge of object properties on grasp kinematics versus kinetics, thus suggesting independent anticipatory processes for grasping.