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Driving Simulation in the Clinic: Testing Visual Exploratory Behavior in Daily Life Activities in Patients with Visual Field Defects
Published on: September 18, 2012
Intact automatic avoidance of obstacles in patients with visual form agnosia
Nichola J Rice1, Robert D McIntosh, Igor Schindler
1Cognitive Neuroscience Research Unit, Wolfson Research Institute, University of Durham, Queen's Campus, Stockton-on-Tees, TS17 6BH, UK.
Experimental Brain Research
|May 9, 2006
Summary
Patients with visual form agnosia, caused by ventral stream damage, can still automatically avoid obstacles during reaching. This suggests the dorsal stream is crucial for obstacle avoidance, not the ventral stream.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Visual Perception
Background:
- Reaching behavior requires integrating target information with obstacle avoidance.
- Previous research implicated the dorsal visual stream in obstacle avoidance.
Purpose of the Study:
- To investigate the role of the ventral visual stream in automatic obstacle avoidance.
- To determine if patients with visual form agnosia can avoid obstacles during reaching tasks.
Main Methods:
- Two studies were conducted with patients exhibiting visual form agnosia due to ventral stream damage.
- Participants performed reaching and grasping tasks with obstacles and a bisection judgment task.
Main Results:
- Patients successfully adjusted reach trajectories to avoid obstacles and modified grip aperture.
- Patients performed significantly worse on bisection judgments compared to controls, but still adjusted reaches.
- Obstacle avoidance was intact despite ventral stream damage.
Conclusions:
- Automatic obstacle avoidance is preserved in individuals with visual form agnosia.
- The dorsal visual stream, not the ventral stream, is critical for automatic obstacle avoidance.
- The ventral stream is not essential for guiding reaching movements around obstacles.
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