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Coordination between the transport and the grasp components during prehension movements
1Instituto di Fisiologia Umana, Università di Parma, Italy.
Experimental Brain Research
|January 1, 1993
Summary
This study found that removing visual cues increased finger movements during object grasping, especially for smaller objects. This suggests vision significantly impacts how we adjust our grasp based on object size and distance.
Area of Science:
- Neuroscience
- Biomechanics
- Human Motor Control
Background:
- Prehension movements involve both transport and grasp phases.
- Visual feedback is crucial for accurate object manipulation.
- Understanding sensory-motor control in grasping is key to human movement studies.
Purpose of the Study:
- To investigate the influence of visual feedback during the transport phase on the grasp component of prehension.
- To analyze kinematics of transport and grasp under visual and non-visual conditions.
- To examine how object size and distance affect grasping without vision.
Main Methods:
- A prehension experiment with visual and non-visual conditions.
- Subjects reached and grasped objects of varying sizes at different distances.
- A matching experiment assessed size estimation via haptics and vision.
Main Results:
- Without vision, maximal finger aperture and velocity increased, particularly for smaller objects.
- Object size was underestimated in the haptic-only condition.
- Hand trajectory variability increased without vision and with greater distances.
Conclusions:
- Visual feedback significantly modulates grasp kinematics, especially for small objects.
- Proprioception and haptics compensate for vision, but with altered precision.
- Motor control strategies adapt based on available sensory information during grasping.