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VISUAL SYSTEM - Coggle Diagram

- - - - axon of ganglion cell join one another, form optic nerve that travels to brain
  - - - allow greater perception of much fainter light in peripheral vision
  - - - most abundant in periphery of eye
      - respond to faint light
    - - most abundant in & around fovea
      - essential for colour vision & more useful in bright light
      - provide 90% of brain's input
    - - important in many activities
- - - - synapse in visual cortex becoming gradually unresponsive to input from that eye
    - - cortical responses become sluggish, don't cause blindness
- - - - 3 main properties
        
        wavelength
        
        hue
        
        intensity
        
        brightness
        
        purity
        
        saturation
    - - accomodation
  - - - contain light-sensitive cells, react to light by creating neural impulses
    - - sensitive to low light
    - - sensitive to fine detail & colour
    - - create chemical reaction to light
  - - - travel to brain via optic nerve
  - - - cells react to simple visual stimuli (e.g. lines, angles)
    - - motion
      - mental imagery
- - - - show blindsight
        
        respond to visual stimuli they're not seeing
  - - - fixed in excitatory & inhibitory zones
      - bar-shaped or edge-shaped receptive fields
    - - located in V1/V2
      - large receptive field
      - respond to patter of light in particular orientation
    - - stronger inhibitory (than complex cells) area at one end of it's bar shaped receptive field
      - respond to bar-shaped pattern of light
- - - - convert energy to electrochemical patterns
      - brain can perceive sight, sound, smell
    - - activity by particular nerve always convey same type of info to brain