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Antipointing: perception-based visual information renders an offline mode of control
1School of Kinesiology, The University of Western Ontario, London, ON, N6A 3K7, Canada.
Experimental Brain Research
|December 17, 2009
Summary
Antipointing movements, unlike direct reaching, are controlled offline using visual perception. This suggests slower visuoperceptual processing supports mirror-symmetrical movements, allowing fewer online corrections.
Area of Science:
- Motor control
- Human movement science
- Cognitive neuroscience
Background:
- Previous research indicated mirror-symmetrical reaching (antipointing) relies on visual information.
- The control mechanisms underlying antipointing, specifically online versus offline control, required further investigation.
Purpose of the Study:
- To determine if visual information supporting antipointing operates primarily in an offline control mode.
- To compare the online versus offline control of antipointing and direct reaching (propointing) movements.
Main Methods:
- Participants performed propointing and antipointing reaching movements to targets in left and right visual fields.
- The proportion of variance (R²) explained by limb position at 75% of movement time was calculated to assess online vs. offline control.
- Endpoint accuracy, stability, and variability were analyzed.
Main Results:
- Direct reaching (propointing) showed accurate and stable endpoints with low R² values, indicating online control.
- Antipointing movements exhibited greater endpoint variability and visual-field specific biases.
- Antipointing movements had higher R² values than propointing movements, suggesting more offline control.
Conclusions:
- Stimulus-driven propointing utilizes metrical visual information for online control.
- Perception-based antipointing relies on relative visual information, leading to offline control.
- The offline control of antipointing is attributed to slower cognitive processing in visuoperceptual networks.
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