Blakemore and Cooper

• background


  • Hirsch and Spinelli investigated the visual cortex of the brain in kittens, the results showed that the kittens had visual deficits and that their visual neuron's had adapted to the environment they had seen in each eye
• aims


  • to investigate the effects of being raised in a restricted visual environment on the kittens
  • investigate the effects of this environment on their behaviour
  • investigate the neurophysiological effects on neurone in the kittens' visual cortex
• sample


  • two kittens who spent the first 2 weeks of their life in the dark
• procedure


  • newborn kittens were raised in a completely dark room for 2 weeks
  • at 2 weeks the kitten was placed inside a cylinder for 5 hours per day, then returning to a dark room
  • the kittens were only able to see either horizontal or vertical lines until they reached 5 months old
  • after 5 months they were put into a well lit room with furniture and their behaviour was observed over several weeks
  • the kittens wore a collar so they could not see their body whilst in the cylinder
• results


  • some initial deficits such as no visual placing when carried towards a table and no startle reflex was shown when objects were thrust towards them.
  • after 10 hours of exposure to a normal visual environment they showed startle responses and visual placing
  • but they still had clumsy and jerky head movements and bumped into objects around the room
  • the kittens were blind to the opposite orientation, unaware of either vertical or horizontal rods in front of them
  • when the kitten's neurons were investigated, their visual neurons had moved to the orientation which they had grown up in
• conclusions


  • the visual environment had changed the kittens' brains
  • the neurons of their brain had rewired themselves based on the environment they were exposed to
  • this is evidence of brain plasticity, at least in kittens