Psyc 351: Psychology of Perception Week 4 Eye, Brain and the Visual Pathways
8/8/2019 Psyc 351Week4
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Psyc 351: Psychology of Perception
Week 4Eye, Brain and the Visual Pathways
8/8/2019 Psyc 351Week4
http://slidepdf.com/reader/full/psyc-351week4 2/46
Adult human eye, axial cross-section, right eye seen from above
Cornea (“hornlike”)IrisScleraPupil
LensHumorsRetinaChoroid / Tapetum
8/8/2019 Psyc 351Week4
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Adult human eye, axial cross-section, right eye seen from above
Pupil diameter
Depth of field
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Pupil SizeA= πr 2 , thus a16-fold increase in light transmission
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Pupil Diameter & Depth of Field
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Horizontal pupils, dilated verticals
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Insects’
compoundeyes
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Accommodation and refraction by cornea and lens
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Adult human eye, axial cross-section, right eye seen from above
Refractive errors:
spherical and cylindrical
MyopiaHyperopia
Astigmatism
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Refractive errors
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Floaters
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Blood
vessels
in the
eye
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The
Retina
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Retina
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The
Retina
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Rods (120 million/eye)
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Cones (8 million/eye)
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Retina, continued
• Duplex structure: Photopic and Scotopic
• Collector cells (Horizontal and Amacrine)
• Sensitivity - acuity tradeoff
• Bleaching of photopigments
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Pathways to the Brain
Optic nerve, myelin sheath
Optic chiasmLateral geniculate
Visual cortex
Retinotopic mapsPrimate cortex
Wiring diagram
Dorsal vs. Ventral Routes
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Pathways to the BrainOptic nerve, myelin sheathOptic chiasm
Lateral geniculate
Visual cortex
Retinotopic maps
Primate cortex
Wiring diagram
Dorsal vs. Ventral pathways
8/8/2019 Psyc 351Week4
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Pathways to the BrainOptic nerve, myelin sheath
Optic chiasmLateral geniculateVisual cortexRetinotopic maps
Primate cortex
Wiring diagram
Dorsal vs. Ventral Routes
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Pathways to the BrainOptic nerve, myelin sheath
Optic chiasm
Lateral geniculateVisual cortex
Retinotopic maps
Primate cortex
Wiring diagram
Dorsal vs. Ventral
pathways
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PathwaysOptic nerve, myelin sheath
Optic chiasm
Lateral geniculate
Visual cortexRetinotopic maps
Primate cortex
Wiring diagram
Dorsal vs. Ventral paths
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Pathways to the BrainOptic nerve, myelin sheath
Optic chiasm
Lateral geniculate
Visual cortex
Retinotopic mapsPrimate cortex
Wiring diagram
Dorsal vs. Ventral paths
P th
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PathwaysOptic nerve, myelin sheath
Optic chiasm
Lateral geniculate
Visual cortex
Retinotopic mapsPrimate cortexWiring diagram
Dorsal vs. Ventral paths
P th
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PathwaysOptic nerve, myelin sheath
Optic chiasm
Lateral geniculate
Visual cortex
Retinotopic mapsPrimate cortexWiring diagram
Dorsal vs. Ventral paths
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Coding Processes in Vision
Steady state vs. change
Conceptual model of retinaLateral inhibition: Limulus, eye
Receptive fields
LGN receptive fieldsSimple cells
Motion cells in Area MTHypercolumns
V1 – V5 Summary
Grandmother cells
C di
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CodingSteady state vs. change
Conceptual model of retina
Lateral inhibition: Limulus, eyeReceptive fields
LGN receptive fields
Simple cells
Motion cells in Area MT
HypercolumnsV1 – V5 Summary
Grandmother cells
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C di
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CodingSteady state vs. change
Conceptual model of retina
Lateral inhibition: Limulus, eyeReceptive fields
LGN receptive fieldsSimple cells
Motion cells in Area MT
HypercolumnsV1 – V5 Summary
Grandmother cells
C di
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CodingSteady state vs. change
Conceptual model of retina
Lateral inhibition: Limulus, eyeReceptive fields
LGN receptive fields
Simple cellsMotion cells in Area MT
HypercolumnsV1 – V5 Summary
Grandmother cells
C di
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CodingSteady state vs. change
Conceptual model of retina
Lateral inhibition: Limulus, eyeReceptive fields
LGN receptive fields
Simple cells
Motion cells in Area MT
HypercolumnsV1 – V5 Summary
Grandmother cells
Coding
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CodingSteady state vs. change
Conceptual model of retina
Lateral inhibition: Limulus, eyeReceptive fields
LGN receptive fields
Simple cells
Motion cells in Area MT
HypercolumnsV1 – V5 Summary
Grandmother cells
Coding
8/8/2019 Psyc 351Week4
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CodingSteady state vs. change
Conceptual model of retina
Lateral inhibition: Limulus, eyeReceptive fields
LGN receptive fields
Simple cells
Motion cells in Area MT
HypercolumnsV1 – V5 Summary
Grandmother cells
Coding
8/8/2019 Psyc 351Week4
http://slidepdf.com/reader/full/psyc-351week4 37/46
CodingSteady state vs. change
Conceptual model of retina
Lateral inhibition: Limulus, eyeReceptive fields
LGN receptive fields
Simple cells
Motion cells in Area MT
HypercolumnsV1 – V5 SummaryGrandmother cells
8/8/2019 Psyc 351Week4
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“The Movies in our Eyes”Frank Werblin & Botond Roska
Scientific American, April 2007
Key idea: the retina not only provides
Image sharpening through lateral
Inhibition and color separation.
It provides up to 12 real-time “movies”
coding for abstract properties
in the image.
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Human Behavioral Evidence
• Hermann Grid
• Mach Bands, model• Aftereffects: McCollough, tilt, waterfall
• Fortification images
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Human EvidenceHermann GridMach Bands, model
Aftereffects:
McCollough
TiltWaterfall
Fortification images
Human
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Human
EvidenceHermann Grid
Mach Bands, model
Aftereffects:McCollough
Tilt
Waterfall
Fortification images
Human
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Human
EvidenceHermann Grid
Mach Bands, model
Aftereffects:McCollough
Tilt
Waterfall
Fortification images
Human
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Human
EvidenceHermann Grid
Mach Bands, model
Aftereffects:McCollough
Tilt
Waterfall
Fortification images
[Excel implementation of model]