Visual anatomy and perception

Frequency (Vision)

Frequency (Vision)

-High frequency ->short wavelength (blue color) -Low frequency-> long wavelength (reddish color)

Amplitude(Vision)

-Great Amplitude->tall (bright colors) -Small Amplitude -> short (dull colors)

Cornea

-eyes clear protective outer layer protecting the pupil and iris (where light enters first)

Pupil

-small adjustable opening in center of the eye (light passes through it)

Iris

-Ring of muscle tissue -Forms the colored portion of the eye -controls the size of pupil by expanding and constricting over the pupil Light enters the eye through an opening in the iris

Lens

-transparent structure behind the pupil -changes shape to help focus images on the retina accommodations -see close objects clear but not far ones

Retina

-along the back of the eye (light-sensitive inner surface) -contains rods and cones -transduction Contains visual receptor cells

What happens in the retina?

-light waves are traduced into neural impulses by rods and cones..then are passed to the cells

Rods

-located on the retinas outer edge -sensitive in dim light (meaning they work in dim light) -detect black, white, and gray and are sensitive to movement -rods are necessary for peripheral/ twilight vision when cones don't respond have a low absolute threshold to light

Cones

-cluster in and around fovea

• function in daylight... becomes unresponsive in dim light (this is why we cant see color in the dark) -they detect detail and create color sensations.

Fovea

-central focal point of retina -area of greatest visual sharpness of focus

Optic nerve

• made of axons and ganglion cells -leaves through the back of the eye... carries neural impulses from the eye to the thalamus and then to the visual cortex

Blind spot

-point where optic nerve leaves the eye

Young Helmholtz Theory

-3 different types of color receptors (cones) -red -green -blue -can produce any color

Parallel Processing

-seeing color, shape, depth,and motion of objects at once

How do we see?

-retina processing -feature detection -parallel processing -Reconition

feature detection

-The ability to detect certain types of stimuli, like movements, shape, and angles, requires specialized cells in the brain called feature detectors.