As the primary sensory organ for vision, the eye captures and transmits light waves from the environment. These waves initiate the process of sight by entering through the pupil after passing across the cornea.

How the eye functions

Many different conditions can cause visual impairment or blindness. 

Vision impairment and blindness

- Visual information is first processed by cells in the retina 
    - photoreceptors, bipolar cells, ganglion cells, horizontal cells, and amacrine cells
- Axons of ganglion cells make up the optic nerve, which transmits this visual information to the lateral geniculate nucleus (LGN) and the superior colliculus of the brain
- Neurons of the LGN synapse on the primary visual cortex, in the occipital lobe

Neural signals from the eye to the brain

- The visual cortex has many regions that process visual information
- Most visual information passes through the primary visual cortex, or area V1 or Brodmann area 17
- There are many other areas of the visual cortex that have important roles in vision

Brain regions involved in sight

- Sensory stimulus region and features that elicit a neuronal response
- Provides information about the function of a cell
- Neurons at different levels of the visual systems have different receptive fields, and therefore, different functions in vision

Receptive fields of visual system

David Hubel and Torsten Wiesel were neurophysiologists whose groundbreaking research on the visual system earned them the 1981 Nobel Prize in Medicine. Over two decades of collaboration, they made fundamental discoveries about how the brain processes visual information, particularly regarding the neurology of perception.

Hubel and Wiesel's Research on the Visual System

- How the eye functions
- Neural signals to the brain regions
- Receptive fields
- Brain regions involved in sight
- Vision impairment and blindness
- Visual illusions

Trinity College (CT)

University of Michigan - Ann Arbor

University of Colorado at Boulder

People tend to use a high amount of visual information to inform their daily activities. There is also a lot of sensory information coming in through the eyes, which makes the visual system a highly researched field of neuroscience. 

Vision

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

Many structures in the eye work together to "see"
- Cornea
- Lens
- Ciliary muscles
- Pupil
- Extraocular muscles
- Retina
- Fovea
- Iris
- Optic nerve

Anatomy of the Visual System

Images are processed  in a manner constrained by the design of visual systems. As a result, some image features can become distorted in ways that alter our perception.

Optical Illusions

Topics in Vision

Vision References

Depth perception is the cognitive ability to perceive the world in three dimensions (3-D) and to understand the spatial relationships between objects. This capacity allows for the description of objects' relative positions, such as being in front, behind, above, below, or to the side of one another.

Depth Perception

There are two primary theories that explain how humans perceive color: the trichromatic theory and the opponent-process theory. These models describe the mechanisms through which the visual system processes wavelength information to create the experience of color.

Theories of Color Perception

Using your understanding of the visual process, explain why Alex and Ben can have two completely different interpretations of the same visual stimulus.

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