Related Experiment Video
Updated: Aug 12, 2026
04:43
Visualizing Visual Adaptation
Published on: April 24, 2017
Changes of visual sensitivity caused by on- and off-transients
Vision Research
|January 1, 1982
Summary
A brief light surround near the retina
Area of Science:
- Visual neuroscience
- Retinal physiology
Background:
- Understanding retinal sensitivity is crucial for vision research.
- Scotopic conditions and absolute threshold are key to studying low-light vision.
Purpose of the Study:
- To investigate how light changes in one retinal area affect sensitivity in adjacent areas.
- To explore the dynamic interplay between surround stimuli and test spots under scotopic conditions.
Main Methods:
- Experiments conducted under low scotopic conditions near absolute visual threshold.
- Utilized brief annular surrounds and test spots to measure retinal sensitivity.
- Investigated effects with stimuli presented to the same or different eyes.
Main Results:
- A brief annular surround transiently decreased retinal sensitivity at its onset and offset.
- The surround increased sensitivity for test spots shortly after its offset.
- Stimuli presented to different eyes showed reduced sensitivity at annulus onset but minimal effect at offset.
Conclusions:
- Retinal sensitivity is dynamically modulated by light changes in adjacent areas.
- The findings challenge the concept of an irreducible noise limit in dark- and dim-light vision.
- Suggests active neural mechanisms influencing visual sensitivity beyond simple noise floor.
Related Concept Videos
01:32The Retina
The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.
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,...
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...
01:21Sensation
Sensory receptors are specialized neurons that respond to specific types of external stimuli, initiating the process known as sensation. This occurs when sensory input, such as light entering the eye, is detected by these receptors, causing chemical changes in the cells of the retina. These cells then convert the sensory stimulus into action potentials that are transmitted to the central nervous system, a process termed transduction.
Absolute thresholds can quantify the sensitivity of sensory...
Absolute thresholds can quantify the sensitivity of sensory...
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.