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Related Concept Videos

Vision

Vision

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.

Color Vision

Color 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.

Depth Perception and Spatial Vision

Depth Perception and Spatial Vision

Depth perception is the ability to perceive objects three-dimensionally. It relies on two types of cues: binocular and monocular. Binocular cues depend on the combination of images from both eyes and how the eyes work together. Since the eyes are in slightly different positions, each eye captures a slightly different image. This disparity between images, known as binocular disparity, helps the brain interpret depth. When the brain compares these images, it determines the distance to an object.

Visual System

Visual System

Light enters the eye through the cornea, a transparent, dome-shaped surface covering the surface of the eyeball that helps to direct and focus incoming light. This light is then channeled toward the pupil, an adjustable opening whose size is controlled by the iris. The iris, a pigmented muscle, regulates the amount of light entering the eye by contracting or dilating the pupil, thereby ensuring optimal light levels for clear vision.
Once through the pupil, the light passes through the lens, a...

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Related Experiment Video

Updated: May 11, 2026

Central and Divided Visual Field Presentation of Emotional Images to Measure Hemispheric Differences in Motivated Attention

Central and Divided Visual Field Presentation of Emotional Images to Measure Hemispheric Differences in Motivated Attention

Published on: November 16, 2017

Emotion-specific modulation of early visual perception.

Jeffrey R Nicol¹, Steven Perrotta, Sabina Caliciuri

¹a Department of Psychology , Nipissing University , North Bay , ON , Canada.

Cognition & Emotion

|May 28, 2013

Summary

This summary is machine-generated.

Fearful facial expressions enhance low spatial-frequency vision and impair high spatial-frequency vision. Disgust expressions, however, impair low spatial-frequency vision, suggesting emotion

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Area of Science:

Cognitive Neuroscience
Visual Perception
Emotional Processing

Background:

Fearful facial expressions are known to modulate visual perception, particularly affecting low and high spatial frequencies.
This modulation is hypothesized to stem from the activation of the magnocellular visual pathway leading to the amygdala.

Purpose of the Study:

To investigate the generality of emotional effects on early visual processing.
To compare the impact of disgust, fear, and neutral facial expressions on orientation sensitivity at different spatial frequencies.

Main Methods:

Participants' orientation sensitivity was assessed for low and high spatial-frequency targets.
Exposure to different facial expressions (disgust, fear, neutral) preceded visual perception tasks.

Main Results:

Fearful expressions enhanced low spatial-frequency vision and impaired high spatial-frequency vision.
Disgust expressions, similar to neutral expressions, impaired low spatial-frequency vision and enhanced high spatial-frequency vision.

Conclusions:

The effect of fear on visual perception is not a universal emotional response.
These findings suggest that the observed effects may be specific to fear or linked to amygdala activation.