Sperry

• What year was the split brain study conducted by Sperry?

  1968
• What does contra-lateral control in the brain refer to?

  Opposite hemisphere processes sensory and motor activity
• Which hemisphere processes information from the right visual field?

  Left hemisphere
• What is the role of the corpus callosum?

  • Bundle of nerve fibers
  • Connects left and right hemispheres
  • Allows electrical signals to transfer
• How does damage to the corpus callosum affect seizures?

  Reduces seizures in patients
• What was the purpose of the split-brain operation?

  Treat severe epilepsy not responsive to medication
• How many patients did Vogel and Bogen perform the surgery on?

  24 patients
• What were the findings of Vogel and Bogen's study on seizures?

  Seizures were markedly reduced
• Where is language primarily located in the brain?

  Left hemisphere
• Why can only objects presented to the RVF/right hand be recognized?

  Because language is in the left hemisphere
• What was Sperry's previous research focus before studying humans?

  Procedures on cats and monkeys
• What does each hemisphere of the brain have?

  Its own memory and stream of consciousness
• What was the aim of Sperry's study?

  • Study psychological effects of hemisphere disconnection
  • Understand functions of left and right hemispheres
• What effect does corpus callosum disconnection have on the brain?

  It prevents communication between the hemispheres
• What was the method used in Sperry's study?

  • Quasi-experiment
  • Independent variable: presence/absence of split brain
  • Dependent variables: naming, recognition, moving hands, drawing
• How does the disconnection of the corpus callosum affect memory?

  Each hemisphere retains separate memories
• How many participants were involved in Sperry's study?

  11 split brain participants
• What was the handedness of all participants in Sperry's study?

  All right handed
• What materials were used in Sperry's study?

  Translucent screen and standard projector
• What types of images were presented in Sperry's study?

  A dollar sign and a key
• What was the procedure for the visual task in Sperry's study?

  • Image presented to one visual field
  • Images shown for 1/10th of a second
  • Participants asked to draw images seen
• What could participants do when images were presented to the RVF only?

  Name the object and find it with right hand
• What was the response when images were presented to the LVF only?

  They couldn't name it but could find it
• What were the results for both visual fields in Sperry's study?

  • RVF: Can name object seen
  • LVF: Says they saw nothing but can draw
  • Surprised by what they drew
• What was the tactile task in Sperry's study?

  • Object placed in left or right hand
  • Asked to name the object
  • Asked to find it in a bag of objects
• What were the tactile results when an object was placed in the right hand?

  Object could be named
• What were the tactile results when an object was placed in the left hand?

  Could be found with the same hand
• What was the visual and tactile task in Sperry's study?

  • Image presented to left or right visual field
  • Participants find object using touch
  • Cannot see array of objects
• What were the results of the visual and tactile tasks?

  Participants found objects with congruent hand
• What was the test of the right hemisphere in Sperry's study?

  • Geometric shapes presented to both visual fields
  • Nude picture flashed to LVF
  • Participants asked if they saw anything else
• What were the results of the test of the right hemisphere?

  Participants blushed and giggled, unaware why
• Why did participants blush and giggle during the right hemisphere test?

  Right hemisphere cannot produce speech