1. Vision Stimulus: Light (Elecro-magnetic radiation) Receptor: Cones and Rods.

1. Vision

Stimulus: Light (Elecro-magnetic radiation)

Receptor: Cones and Rods

• Approximately – 6-7 million cones– 75-150 million rods

• Cones are most sensitive to color and higher levels of light

• Rods most effective in lower light conditions, black and white etc.

Light Energy

Light Energy

Cornea

Light Energy

CorneaRefracts (bends) the light

Light Energy


Focused through the pupil

Light Energy



Iris Contracts or dilates

to allow more or less light

Light Energy





Light enters the lens

Light Energy




Bends and focuses

Light Energy



Light Energy




Bends and focuses

Light EnergyImage is inverted and displayed on the retina



Light Energy




Bends and focuses


Transduction



Light Energy




Bends and focuses


Transduction Transfer of Light Energy to Neural impulses on photo-receptor cells



Light Energy




Bends and focuses


Transduction



Transfer of Light Energy to Neural impulses on photo-receptor cells

Chemical changes in bipolar and ganglion cells activate rods and cones

Light Energy




Bends and focuses


Transduction





Cones create neural impulse for color and rods create impulse for shape, border and night vision

Light Energy




Bends and focuses


Transduction





Impulses channeled to the Optic Nerve


Light Energy




Bends and focuses


Transduction







Impulse travels through the thalamus, then (if worthy) on to the visual cortex in the occipital lobe

Light Energy




Bends and focuses


Transduction








Visual cortex processes impulses into an image

Light Energy




Bends and focuses


Transduction







Visual cortex processes impulses into an image

Perception Occurs


Binocular Vision

• Monocular depth cues allow us to see in 3D with one eye, but it’s best with both– Because left and right eyes see things a little

differently – binocular disparity

• The combination of two images into the one we see– Example: Finger Sausage

Color Blindness

• 8% of Men• 1% of Women• Usually red and green• Sometimes yellow and Blue• Very few are totally color blind

After Image

• A visual impression that persists after the removal of the stimulus which originally caused it.– Example: American Flag, Jesus

Autosereogram

• Illusion of depth through binocular cues• Formed by superimposing 2 repeating

patterns, which are slightly offset

1. Vision Stimulus: Light (Elecro-magnetic radiation) Receptor: Cones and Rods.

Documents

Transcript of 1. Vision Stimulus: Light (Elecro-magnetic radiation) Receptor: Cones and Rods.