The eye, the retina, and sensory transduction

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The eye, the retina, and sensory transduction

• PS2009/10 Lecture 2

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The Eye
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Accommodation
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Accommodation
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The Eye
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The Retina
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Photoreceptor distribution
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Photoreceptors
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Photoreceptors

• Photoreceptors contain a photopigment
• Photopigments are chemicals capable of reacting
  to light
• rod - rhodopsin
• cones - iodopsin (3 types)
• two components
• opsin
• retinal

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The Retina
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Ganglion Cells
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Anatomical differences between Ganglion Cells

• Parvo
• small cell body
• dense branching
• short branching
• majority of cells

• Magno
• large cell body
• sparse branching
• long branches
• minority of cells

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Physiological differences between Ganglion cells

• Parvo
• slow conduction rate
• sustained response
• small receptive field
• low-contrast sensitivity
• colour sensitive

• Magno
• rapid conduction rate
• transient response
• large receptive field
• high-contrast sensitivity
• colour blind

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Behavioural differences between Ganglion cells

• Parvo
• detailed form analysis
• spatial analysis
• colour vision

• Magno
• motion detection
• temporal analysis
• depth perception