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Assessing Binocular Central Visual Field and Binocular Eye Movements in a Dichoptic Viewing Condition
Published on: July 21, 2020
Equal degrees of object selectivity for upper and lower visual field stimuli.
Lars Strother1, Adrian Aldcroft, Cheryl Lavell
1Department of Physiology and Pharmacology, Canadian Institutes of Health Research Group for Action and Perception, University of Western Ontario, Ontario, Canada. lstroth@uwo.ca
Journal of Neurophysiology
|August 20, 2010
Summary
Functional MRI studies show the lateral occipital cortex (LO) distinguishes objects from non-objects equally in both visual field locations. Object selectivity in the LO region remains consistent despite variations in stimulus position.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Visual Perception
Background:
- Functional MRI (fMRI) studies commonly use blood oxygen level-dependent (BOLD) responses to identify object-selective regions in the human brain.
- The lateral occipital cortex (LO) is known for object selectivity and recent evidence suggests retinotopic organization, implying it processes both object and location information.
- It is unclear if the object selectivity of the LO is influenced by stimulus location, specifically whether responses to scrambled objects vary with retinal position.
Purpose of the Study:
- To investigate whether the object selectivity of the human lateral occipital cortex (LO) varies with retinal stimulus position.
- To determine if responses to scrambled objects show similar position dependence as responses to intact objects.
- To ascertain if the degree of object selectivity in LO is consistent across different visual field locations.
Main Methods:
- Used a conventional functional localizer approach with fMRI to identify the human visual area LO.
- Compared BOLD responses to intact objects versus scrambled objects.
- Presented stimuli to either the upper visual field (UVF) or lower visual field (LVF) to assess position-dependent effects.
Main Results:
- Confirmed position-dependent responses to intact objects in the LO, consistent with previous findings.
- Observed a similar degree of position dependence for scrambled objects.
- Found that object selectivity in the LO did not differ significantly between the UVF and LVF stimuli.
Conclusions:
- The lateral occipital cortex (LO) demonstrates equal ability to discriminate objects from non-objects across different visual field locations based on BOLD response.
- Despite stronger overall responses to objects in the lower visual field (LVF), the relative object selectivity remains consistent.
- These findings suggest that LO's object discrimination capabilities are robust to variations in retinal stimulus position.
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