Lateralisation

• What does hemispheric lateralisation refer to?

  Functional differences between the brain's hemispheres
• What is contralateral function?

  Opposite hemisphere controls opposite body side
• What is a commissurotomy?

  Surgical severing of the corpus callosum
• Why are split brain patients unique?

  They have severed corpus callosum for epilepsy
• What was the aim of Sperry's 1968 study?

  To study the effects of hemispheric lateralisation
• What happens when a split brain patient sees an object in their left visual field?

  They cannot name it due to right hemisphere processing
• If a split brain patient sees an object in their right visual field, what can they do?

  They can name it correctly due to left hemisphere processing
• What happens if a split brain patient is asked to draw an object seen in their left visual field?

  They can draw it with their left hand
• What is the outcome if a split brain patient is asked to find an object seen in their left visual field with their right hand?

  They cannot find it due to hemisphere processing
• What happens when a split brain patient is shown a composite word?

  They can say the word processed by the left hemisphere
• How do split brain patients recognize faces?

  They are more likely to select the face processed by the right hemisphere
• What are some abilities of the right hemisphere in split brain patients?

  Can carry out simple math and sort objects
• What are the key findings of Sperry's study on split brain patients?

  • Right hemisphere processes left visual field
  • Left hemisphere processes right visual field
  • Left hand can select objects seen by right hemisphere
  • Right hand cannot select objects seen by left hemisphere
  • Drawings are better with left hand
  • Composite words lead to naming the left hemisphere word
• How does the left hemisphere's function differ from the right hemisphere's function?

  Left hemisphere is language-focused, right is visual
• What would happen if a split brain patient is shown a nude picture among geometric shapes?

  They may giggle but won't recall seeing it
• How can unusual behavior in split brain patients be tested in an experiment?

  • Use a split visual field setup
  • Present visual or auditory stimuli
  • Require verbal or visuospatial responses
  • Tasks may include drawing or matching
• What are the key terms related to lateralisation?

  • Lateralisation: Brain function control by one hemisphere
  • Split brain patients: Individuals with severed corpus callosum
  • Commissurotomy: Surgery to sever the corpus callosum
  • Contra-lateral function: Opposite hemisphere controls opposite body side
• What are the key areas of the brain involved in lateralisation?

  Motor, somatosensory, visual, auditory, language
• Which areas of the brain are specifically mentioned in relation to language?

  Broca’s and Wernicke’s areas
• What type of research design was used in Sperry's study?

  Quasi Experiment
• What is a strength of Sperry's study regarding its methodology?

  Controlled conditions with standardised procedures
• What is a weakness of Sperry's study related to ecological validity?

  Patients can adjust visual position in real life
• What issue is mentioned regarding the sample size in split brain research?

  Declining number of split brain patients
• How many participants were in Sperry's original study?

  11 participants
• What generalization issue arises from the small sample size in split brain research?

  Limited ability to generalize findings
• What is the main reason for lateralisation according to Rogers et al (2004)?

  It creates more processing capacity
• What did Rogers et al (2004) find about brain lateralisation in chickens?

  It helps perform two tasks simultaneously
• Why is it difficult to apply findings from animal studies to humans?

  Humans perform more complex cognitive processes
• What did Szaflarski et al (2006) discover about language lateralisation with age?

  It becomes more lateralised until age 25
• What happens to lateralisation after the age of 25 according to Szaflarski et al (2006)?

  Lateralisation decreases with each decade
• What implication does the change in lateralisation with age suggest?

  Older adults may use both hemispheres
• What does Gazzaniga (1998) suggest about early discoveries from split-brain research?

  Some have been disconfirmed by recent findings
• What did Turk et al (2002) find about patient J.W.?

  He developed speech capacity in the right hemisphere
• What does the case of J.W. suggest about language lateralisation?

  Language may not be limited to the left hemisphere
• What does the case of J.W. support regarding brain function?

  It supports the concept of brain plasticity
• What are the strengths and weaknesses of Sperry's study?

  Strengths:

  • Controlled conditions
  • Standardised procedures

  
  

  Weaknesses:

  • Lack of ecological validity
  • Small sample size issues
• What changes occur in lateralisation as we age?

  • Increases until age 25
  • Decreases with each decade after 25
  • Functions may switch from lateralised to bilateral
• What are the implications of findings from split-brain research?

  • Language may not be exclusive to one hemisphere
  • Brain can recover functions post-surgery
  • Research findings may not generalize to all humans
• What is the concept of hemispheric lateralization?

  Functions are controlled by one brain side
• How do the left and right hemispheres of the brain interact with the body?

  Left hemisphere controls right body side