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Published on: December 11, 2017
"Real-time" obstacle avoidance in the absence of primary visual cortex
Christopher L Striemer1, Craig S Chapman, Melvyn A Goodale
1Canadian Institutes of Health Research Group on Action and Perception, Centre for Brain and Mind, Department of Psychology, The University of Western Ontario, London, Ontario, Canada N6A 5C2.
Summary
This study shows that the brain can avoid obstacles in real-time without using primary visual cortex (V1). This suggests faster visual processing pathways control movement, even without conscious sight.
Area of Science:
- Neuroscience
- Visual Perception
- Motor Control
Background:
- Obstacle avoidance during reaching is crucial for daily activities.
- Previous research implicated the dorsal visual stream in the posterior parietal cortex for this function.
- The origin of visual input to these dorsal-stream mechanisms remains unclear.
Observation:
- An individual with damage to the primary visual cortex (V1) and resulting hemianopia demonstrated sensitivity to unseen obstacles in their blind visual field.
- This sensitivity to obstacles in the blind field was abolished when a brief delay was introduced before the reaching task.
Findings:
- Visual input from the primary visual cortex (V1) is not essential for real-time obstacle avoidance.
- Subcortical visual pathways can rapidly process visual information for motor control without V1 input.
- The timing of visual input significantly impacts the effectiveness of obstacle avoidance mechanisms.
Implications:
- Challenges the necessity of V1 for immediate visual-guided motor behaviors.
- Highlights the role of "primitive" subcortical visual pathways in everyday actions.
- Provides insights into the temporal dynamics of different visual processing streams.
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