Visual control centre

• visual cortex

  • at back of brain
  • recieves + processes info from both eyes
• what's in the VC

  • ocular dominance columns
  • with neurones that respond to input from eyes
  • dominance columns alternate between left & right eye
  • no. genetically determined
  • critical period after birth ->
  • visual experience maintains & refine ocular dominance columns
• what did Hubel & Wiesel do?

  • covered 1 eye of young monkey
  • during critical period
• what did Hubel & Wiesel find?

  • in deprived eye
  • neurones in VC
  • no longer responded
• explain results of Hubel & Wiesel?

  • you need visual input during critical period
  • for normal development of VC
  • permanent effect -> so changes in brain irreversable after critical period =
• How does visual development take place?

  • before visual development
  • the synapses in the ocular dominance columns overlap
  • in the critical period,
  • young animals need to recieve light stimulus
• light stimulus in critical window

  • causes more NTs to be released at synapses in the correct ocular dominance columns
  • While competing synapses release less NTs
  • Those synapses - weakened + eliminated
  • While the synapses that release alot - strengthened
  • Ensures ODC organised properly