Related Experiment Video
Updated: May 16, 2026
05:39
Generating Strictly Controlled Stimuli for Figure Recognition Experiments
Published on: March 18, 2019
Two critical periods in early visual cortex during figure-ground segregation
Martijn E Wokke1, Ilja G Sligte, H Steven Scholte
1Cognitive Neuroscience Group, Department of Psychology, University of Amsterdam Weesperplein 4, 1018 XA, Amsterdam, The Netherlands ; Cognitive Science Center, University of Amsterdam Sarphatistraat 104, 1018 GV, Amsterdam, The Netherlands.
Brain and Behavior
|November 22, 2012
Summary
This study reveals that early visual cortex (V1/V2) is crucial for both initial figure border detection and later stages like surface segregation in visual perception. Disrupting V1/V2 at different times impacts these distinct figure-ground segregation processes.
Area of Science:
- Neuroscience
- Visual Perception
- Cognitive Science
Background:
- Figure-ground segregation is vital for visual perception.
- The precise role and timing of early visual areas (V1/V2) in this process remain unclear.
- V1/V2 are implicated in both early border detection and later segregation stages.
Purpose of the Study:
- To causally investigate the role of early visual cortex (V1/V2) in different stages of figure-ground segregation.
- To determine the temporal dynamics of V1/V2 involvement in visual processing.
Main Methods:
- Used transcranial magnetic stimulation (TMS) to briefly disrupt activity in V1/V2 at specific time points.
- Presented stimuli differentiating figure border detection and surface segregation.
- Recorded electroencephalographic (EEG) signals to analyze neural correlates.
Main Results:
- Early TMS (96-119 ms) disrupted figure detection, border ownership, and surface segregation.
- Late TMS (236-259 ms) selectively impaired surface segregation performance.
- Neural correlates of all tested stages were affected by early V1/V2 disruption.
Conclusions:
- V1/V2 are essential for the initial detection of figure borders.
- V1/V2 also play a causal role in later, more complex stages of figure-ground segregation, including surface segregation.
- These findings clarify the temporal contribution of early visual areas to complex visual perception.
More Related Videos
Related Concept Videos
01:21Gestalt Principles of Perception
Gestalt principles provide a framework for understanding how humans perceive objects as unified wholes within their context. These principles are essential in explaining the cognitive processes that make sense of complex visual stimuli by organizing them into coherent groups. One fundamental principle is proximity, which posits that objects located close to each other are perceived as a collective group. For instance, when dots are positioned near one another, the visual system interprets them...
01:24Color Vision
Color perception begins in the retina, the light-sensitive layer at the back of the eye. Two main theories explain how colors are seen: the trichromatic theory and the opponent-process theory. The trichromatic theory, proposed by Thomas Young in 1802 and extended by Hermann von Helmholtz in 1852, suggests that color vision is based on three types of cone receptors in the retina. These cones are sensitive to different but overlapping ranges of wavelengths corresponding to red, blue, and green.
01:21Association Areas of the Cortex
Association areas are regions of the cerebral cortex that do not have a specific sensory or motor function. Instead, they integrate and interpret information from various sources to enable higher cognitive processes such as memory, learning, and decision-making. Some key association areas include the following:
Prefrontal Association Area: This area is located in the frontal lobe and is involved in planning, decision-making, and moderating social behavior. It connects with primary motor areas,...
Prefrontal Association Area: This area is located in the frontal lobe and is involved in planning, decision-making, and moderating social behavior. It connects with primary motor areas,...
01:20Parallel Processing
The brain processes sensory information rapidly due to parallel processing, which involves sending data across multiple neural pathways at the same time. This method allows the brain to manage various sensory qualities, such as shapes, colors, movements, and locations, all concurrently. For instance, when observing a forest landscape, the brain simultaneously processes the movement of leaves, the shapes of trees, the depth between them, and the various shades of green. This enables a quick and...
01:24Vision
Vision is the result of light being detected and transduced into neural signals by the retina of the eye. This information is then further analyzed and interpreted by the brain. First, light enters the front of the eye and is focused by the cornea and lens onto the retina—a thin sheet of neural tissue lining the back of the eye. Because of refraction through the convex lens of the eye, images are projected onto the retina upside-down and reversed.
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...