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Centre-surround interactions in response to natural scene stimulation in the primary visual cortex
Kun Guo1, Robert G Robertson, Sasan Mahmoodi
1Institute for Neuroscience and Psychology, Brain and Behaviour Group, School of Biology, Henry Wellcome Building for Neuroecology, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK. kguo@lincoln.ac.uk
The European Journal of Neuroscience
|January 28, 2005
Summary
Visual cortex neurons show surround modulation by natural scenes. This centre-surround interaction in area V1 is sensitive to image contrast and structure, impacting neuronal responses.
Area of Science:
- Neuroscience
- Visual Neuroscience
- Computational Neuroscience
Background:
- Centre-surround interactions are crucial for visual processing.
- Previous studies primarily used artificial stimuli like gratings.
- Natural scenes present complex visual information beyond simple patterns.
Purpose of the Study:
- To investigate centre-surround interactions in the primary visual cortex (V1) using natural scene images.
- To determine how natural scene surrounds modulate neuronal responses within the classical receptive field (CRF).
- To explore the role of contrast and higher-order structures in natural scene-driven surround modulation.
Main Methods:
- Recorded neuronal responses in area V1 of awake, fixating macaques.
- Systematically varied the contrast of natural image surrounds outside the CRF.
- Presented natural image patches within the CRF and analyzed neuronal activity.
- Manipulated natural image surrounds by randomizing Fourier spectrum phases.
Main Results:
- Natural image surrounds significantly modulated neuronal responses for most neurons (67/111), primarily through suppression.
- Modulatory effects were observed early in neuronal responses and depended on surround contrast and structure.
- Randomizing surround image phases reduced centre-surround interaction in a majority of affected neurons (47/67).
Conclusions:
- Centre-surround interaction in V1 extends to natural vision.
- This interaction is sensitive to higher-order structures, like contours, in natural scenes.
- Natural scene statistics, not just simple features, influence visual processing in V1.