Post on 23-Dec-2015
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
CorneaRefracts (bends) the light
Focused through the pupil
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Iris Contracts or dilates
to allow more or less light
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Iris Contracts or dilates
to allow more or less light
Light enters the lens
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light Energy
Iris Contracts or dilates
to allow more or less light
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light EnergyImage is inverted and displayed on the retina
Iris Contracts or dilates
to allow more or less light
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light EnergyImage is inverted and displayed on the retina
Transduction
Iris Contracts or dilates
to allow more or less light
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light EnergyImage is inverted and displayed on the retina
Transduction Transfer of Light Energy to Neural impulses on photo-receptor cells
Iris Contracts or dilates
to allow more or less light
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light EnergyImage is inverted and displayed on the retina
Transduction
Iris Contracts or dilates
to allow more or less light
Transfer of Light Energy to Neural impulses on photo-receptor cells
Chemical changes in bipolar and ganglion cells activate rods and cones
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light EnergyImage is inverted and displayed on the retina
Transduction
Iris Contracts or dilates
to allow more or less light
Transfer of Light Energy to Neural impulses on photo-receptor cells
Chemical changes in bipolar and ganglion cells activate rods and cones
Cones create neural impulse for color and rods create impulse for shape, border and night vision
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light EnergyImage is inverted and displayed on the retina
Transduction
Iris Contracts or dilates
to allow more or less light
Chemical changes in bipolar and ganglion cells activate rods and cones
Cones create neural impulse for color and rods create impulse for shape, border and night vision
Impulses channeled to the Optic Nerve
Transfer of Light Energy to Neural impulses on photo-receptor cells
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light EnergyImage is inverted and displayed on the retina
Transduction
Iris Contracts or dilates
to allow more or less light
Chemical changes in bipolar and ganglion cells activate rods and cones
Cones create neural impulse for color and rods create impulse for shape, border and night vision
Impulses channeled to the Optic Nerve
Transfer of Light Energy to Neural impulses on photo-receptor cells
Impulse travels through the thalamus, then (if worthy) on to the visual cortex in the occipital lobe
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light EnergyImage is inverted and displayed on the retina
Transduction
Iris Contracts or dilates
to allow more or less light
Chemical changes in bipolar and ganglion cells activate rods and cones
Cones create neural impulse for color and rods create impulse for shape, border and night vision
Impulses channeled to the Optic Nerve
Transfer of Light Energy to Neural impulses on photo-receptor cells
Impulse travels through the thalamus, then (if worthy) on to the visual cortex in the occipital lobe
Visual cortex processes impulses into an image
Light Energy
CorneaRefracts (bends) the light
Focused through the pupil
Light enters the lens
Bends and focuses
Light EnergyImage is inverted and displayed on the retina
Transduction
Iris Contracts or dilates
to allow more or less light
Chemical changes in bipolar and ganglion cells activate rods and cones
Cones create neural impulse for color and rods create impulse for shape, border and night vision
Impulses channeled to the Optic Nerve
Impulse travels through the thalamus, then (if worthy) on to the visual cortex in the occipital lobe
Visual cortex processes impulses into an image
Perception Occurs
Transfer of Light Energy to Neural impulses on photo-receptor cells
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