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Eye + Retina (Continued)👁 - Coggle Diagram
Eye + Retina (Continued)
👁
Bipolar Cells
ON bipolar cells✅
Depolarize in response to light ON💡
G-protein coupled glutamate receptors == mGluR6
Glutamate binds in dark
Hyperpolarization
Makes voltage more (+)
Function
Detect light objects in darker background
OFF bipolar cells❎
Depolarize in response to light OFF🌑
AMPA glutamate receptors
Glutamate binds in dark
Depolarization
Makes voltage more (-)
Function
Detect dark objects in lighter background
System of 2 different types of bipolar cells
Gives brain stronger sense🧠
Horizontal Cells
Inhibitory cells releasing GABA
Function
Connect photoreceptors to enhance contrast detection
Light vs dark contrast
Control responses of "center" photoreceptor
Indirectly produce bipolar cell receptive field surround effect
Ganglion Cells
If ON bipolar cells depolarize✅
ON ganglion✅
⚡️Action potential firing rate increases⬆️
Synapse == AMPA glutamate receptors
If OFF bipolar cells depolarize✅
OFF ganglion❎
⚡️Action potential firing rate increases⬆️
Synapse == AMPA glutamate receptors
Types
P-Type
Good at detecting details
Ex. object shape🎁
Parvo == small🐁
Smaller dendritic network
Small receptive fields
ON center
Sudden increase in action potential firing rate, but then decreases slowly (sustained)
M-Type
Good at detecting motion🚙
Magno == large🐘
Wide network of dendrites
Large receptive fields
ON center
Sudden increase action potential firing rate, but then decreases quickly
Antagonistic Center-Surround Receptive Fields
🎯
Discovered by Stephen Kuffler in 1953🧑🔬
ON ganglion cells✅
🌕"likes" light in center + dark in surround🌑
OFF ganglion cells❎
🌑"likes" dark in center + light in surround🌕
🌑Dark in center + light in surround🌕
Hyperpolarizes cells in surround
Horizontal cells stop releasing GABA
🌑Both center + surround == dark🌑
Surround cells hyperpolarizes + center cells depolarize
🌕Both center + surround == light🌕
Surround cells depolarizes + center cells hyperpolarize
🌕Light in center + dark in surround🌑
Hyperpolarizes cells in center
Horizontal cells further hyperpolarize