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Impaired visual competition in patients with homonymous visual field defects
A C Geuzebroek1, A V van den Berg1
1Department Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Postbus 9101, 6500 HB Nijmegen (route 205), The Netherlands.
Neuropsychologia
|February 18, 2017
Summary
Visual training aids recovery from primary visual cortex defects. Patients with visual field defects show altered decision-making, even in intact vision, suggesting rehabilitation needs to address visual decision-making alongside training.
Area of Science:
- Neuroscience
- Ophthalmology
- Cognitive Science
Background:
- Visual field defects from primary visual cortex lesions can partially recover with training.
- Standard training tasks neglect complex natural visual environments with interacting stimuli.
- Visual competition is crucial for search and detecting unexpected events.
Purpose of the Study:
- To investigate visual decision-making in patients with visual field defects.
- To assess how recovered visual fields compete for attention with intact visual fields.
- To explore competition mechanisms (feed-forward vs. feedback inhibition).
Main Methods:
- A saccade target-selection paradigm comparing nine patients with visual field defects to healthy controls.
- Participants chose the brighter of two flashed targets.
- Intensity reversal of targets during flashes to probe competition dynamics.
Main Results:
- Healthy controls exhibited a primacy effect, preferring the initially brighter target.
- Patients' choice behavior differed significantly from controls, even in their 'intact' visual field.
- Patients showed reduced preference for the brighter target and a tendency to guess, indicating slower information integration.
Conclusions:
- Decision-making mechanisms appear similar between patients and controls.
- Patients' choices are influenced by a guessing tendency, even in intact visual fields.
- Rehabilitation should incorporate training for visual decision-making in both defective and intact visual fields.
Keywords:
Decision-making mechanismsHemianopiaHomonymous visual field defectsIntact intrahemispheric competitionIpsilateral visual fieldPerimetry.Recovered visual field competitionStrokeVisual competitionMore Related Videos
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