Glossary
Visual Cortex
What is the visual cortex?
The visual cortex includes cortical areas involved in processing visual information. Primary visual cortex (V1) lies in the occipital lobe; higher visual pathways extend into temporal and parietal regions.
Primary and higher visual areas
V1 receives visual information from the retina through the thalamus. Other visual areas include V2, V3, V4, and V5, which participate in further processing. Connected pathways extend toward temporal regions involved in object recognition and parietal regions involved in spatial information.
Functions
- Visual features and recognition: Connected areas process aspects such as shape, color, and texture, contributing to recognition of objects and scenes.
- Motion: Area V5, also called the middle temporal area (MT), is particularly involved in processing motion, including speed and direction.
- Depth: Visual processing uses binocular information, including differences between the two eyes' images, as well as monocular cues such as shading and perspective.
Associated disorders
Cortical blindness usually follows injury to primary visual cortex on both sides, producing loss of conscious vision even when the eyes and optic nerves are intact. Some reflex responses to light can remain.
Visual agnosia involves difficulty recognizing visual objects or other familiar stimuli despite sufficient basic vision. It concerns higher visual processing and associated pathways.
Why it matters
Seeing light, detecting motion, and recognizing an object are related but different functions. The visual cortex is a network of areas.