Responses in early visual areas to contour integration are context dependent

Area of Science:

• Neuroscience
• Visual Perception
• Cognitive Science

Background:

• Early visual areas are known to process contours.
• The interaction between local and global context in contour processing remains unclear.
• Interarea coordination for coherent structural perception, especially in humans, requires further study.

Purpose of the Study:

• To investigate how local and global context influence contour processing in early visual areas.
• To examine interarea coordination in early visual cortex during contour detection.
• To differentiate neural mechanisms for contour processing with and without background clutter.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
• Observers performed a contour detection task with manipulated Gabor element alignment and background clutter.
• Six regions of interest in V1, V2, and V3 were defined using functional localizers.

Main Results:

• Responses in V1 and V2 target regions were stronger for aligned than unaligned contours in the presence of clutter.
• No significant difference in V1/V2 responses was observed without background clutter.
• V1-V2 coordination increased for aligned contours with clutter, but remained similar without clutter.

Conclusions:

• Different mechanisms support contour processing with and without background distractors.
• Coordination between V1 and V2 plays a crucial role in coherent structure perception, particularly in complex scenes.
• Findings highlight the importance of interarea communication in visual perception.