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Effects of object shape and visual feedback on hand configuration during grasping
Luis F Schettino1, Sergei V Adamovich, Howard Poizner
1Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ 07102, USA.
Experimental Brain Research
|June 5, 2003
Summary
Hand preshaping for grasping involves early, visually independent configuration selection and later, visually guided optimization. This suggests distinct predictive and responsive control mechanisms for grasping movements.
Area of Science:
- Neuroscience
- Biomechanics
- Motor Control
Background:
- Human hand grasping involves gradual shaping to match object geometry.
- Visual feedback and object properties influence hand preshaping during reaching movements.
Purpose of the Study:
- To investigate the role of visual feedback in hand preshaping.
- To differentiate the influence of object shape and visual information on finger and joint movements during grasping.
Main Methods:
- Manipulated object shapes and visual feedback conditions (Full Vision, Object Vision, No Vision).
- Recorded kinematic data of finger and joint angles during reaching and grasping tasks.
- Analyzed movement duration, time to peak aperture, and joint angle patterns.
Main Results:
- Reduced visual feedback increased movement duration and decreased time to peak hand aperture.
- Abduction/adduction (finger spreading) preshaping occurred early and independently of visual feedback.
- Flexion/extension (finger bending) preshaping occurred later, influenced by visual feedback availability.
Conclusions:
- Hand preshaping utilizes at least two control mechanisms: an early predictive phase for basic configuration and a late responsive phase for optimization.
- Grip selection is largely achieved predictively, with visual feedback refining the grasp later in the movement.