Split Brain research

• Hemispheric lateralisation - the fact that some mental processes in the brain are mainly specialised to either the right or the left hemisphere
• Split brain research - refers to studies done of individuals who have be subjected to the surgical separation of their hemispheres (severing their corpus callosum).
• Sperry's study Intro:

  • involved a group of individuals who had all gone through a splitting of their corpus collosum to control epileptic seizures
• Sperry's Procedure:

  • an image/word was projected to the individuals right visual field (processed by left hemisphere) and the same/different image was projected to their left visual field
  • in a normal brain, the corpus collosum would have shared the information between hemispheres, but this couldn't happen with the split brain patients
• Sperry's Findings (1):

  • when a picture was shown to the right vf, they could easily describe what they saw (left hem = language and speech)
  • when it was shown to the left vf, they didn't know what it was/there was nothing there
• Sperry's Findings (2):

  • individuals couldn't attach verbal labels to objects shown to left vf (right hem = visual motor)but could select a physical matching object
• Real world application

  • discovered a number of differences between the 2 hemispheres which can be applied to split-brain patients and explain why their functioning may be different to other typical people
• Reductionist

  • each individual may have differences in their split brains due to surgery/a large interpretation of localisation of function

  there may be other factors contributing to the differences between hemispheres and its reductionist to just say left=speech, right=visual
• Research support

  • Tonnessen et al - found a relationship between having a right superior hemisphere and left handedness/immune system problems

  this supports that hemispherical lateralisation is responsible for many differences and functions
• Left hemisphere - mostly responsible for language and speech
• Right hemisphere - is mostly responsible for visual motor tasks