localisation and lateralisation

• What are the main parts of the brain and their functions?

  • Frontal lobe: Involved in reasoning and problem-solving.
  • Parietal lobe: Processes sensory information.
  • Temporal lobe: Involved in memory and auditory processing.
  • Occipital lobe: Processes visual information.
• What is the role of the left hemisphere of the brain?

  • Responsible for language and analytical tasks.
• What is the role of the right hemisphere of the brain?

  • Responsible for creativity and spatial awareness.
• What is the function of the corpus callosum?

  • Connects the left and right hemispheres of the brain.
• What are the two hemispheres of the brain called?

  • Left hemisphere
  • Right hemisphere
• What is lateralisation in the context of brain function?


  Lateralisation refers to the control of certain physical and psychological functions by a particular hemisphere.
• How does the right hemisphere control the left side of the body?

  Activity on the left-hand side of the body is controlled by the right hemisphere.
• How is visual information processed in the occipital lobe?


  Each eye sends information from the right visual field to the left visual cortex and from the left visual field to the right visual cortex.
• What can damage to the left hemisphere cause in terms of visual perception?


  It can produce blindness in part of the right visual field of both eyes.
• What happens if there is damage to the auditory area?


  It may produce partial hearing loss, with more extensive damage leading to more severe loss.
• What is Broca's area responsible for?

  Broca's area is responsible for speech production.
• What characterizes Broca's aphasia?

  Broca's aphasia is characterized by slow, laborious speech that lacks fluency.
• What did Karl Wernicke identify in the left temporal lobe?


  Wernicke identified an area responsible for language understanding.
• What happens when Wernicke's area is damaged?

  Damage to Wernicke's area results in Wernicke's aphasia, where speech is fluent but meaningless.
• What is the difference between localisation and lateralisation in the brain?

  • Localisation: Specific functions governed by specific areas in the brain.
  • Lateralisation: Certain functions are performed by one hemisphere rather than the other.
• Which hemisphere contains Broca's and Wernicke's areas in most people?


  Both Broca's and Wernicke's areas are located in the left hemisphere.
• How is visual information processed in terms of hemispheric connections?

  • The left visual field (LVF) is connected to the right hemisphere (RH).
  • The right visual field (RVF) is connected to the left hemisphere (LH).
• What is the purpose of split-brain surgery?


  Split-brain surgery is performed to reduce epilepsy by severing connections between the hemispheres.
• What was the procedure used in Sperry's research on split-brain patients?


  Images were projected to one visual field at a time to study how each hemisphere processed the information.
• What were the findings when an object was shown to a participant's right visual field?


  The participant could describe what was seen when the object was shown to the right visual field.
• What happened when an object was shown to the left visual field of a split-brain participant?


  The participant could not describe the object but could select a matching object using their left hand.
• the motor area

  located in the back of the frontal lobe, controls voluntary movement in the opposite side of the body and damage results in a loss of control over fine movements
• the somatosensory area

  located in the front of the pariental lobe, a valley separates the frontal lobe and pariental lobe called the central sulcus

  it is where sensory information is represented (from the skin)
• Brain scan evidence of localisation - Peterson et al


  used brain scans to demonstrate how Wernicke's area was active during a listening task and that Broca's area was active during a reading task, shows different areas have different functions
• Neurosurgical evidence of localisation - Dougherty et al


  The practice of surgically removing and destroying areas of the brain to control aspects of behaviour, discovered in 1950s

  44 OCD patients undergone angulotomy, after 32 weeks 1/3 met criteria for successful response - shows that symptoms and behaviours are localised
• split-brain research - strengths of the methodology


  - experiments made use of highly specialised and standardised procedures

  - typically, participants would be asked to stare at a given point, the 'fixation point'

  - the image projected would be flashed up for 1/10 of a second, meaning the split-brain patient would not have time to move their eyes across the image and so spread the information across both sides of the visual field

  - this allowed Sperry to vary aspects of the basic procedure and ensured that only one hemisphere was receiving information at a time

  = a very useful and well-controlled procedure
• split-brain research - theoretical basis


  Sperry's work prompted a theoretical and philosophical debate about the degree of communication between the two hemispheres in everyday functioning and the nature of consciousness

  other researchers argued that the two hemispheres form a highly integrated system and are both involved in everyday tasks
• split-brain research - issues with generalisation


  many researchers have urged caution in their widespread acceptance, as split-brain patients constitute such an unusual sample of people - there were only 11 who took part in all variations of the basic procedure, all of whom had a history of epileptic seizures, this may have caused unique changes in the brain that have influenced the findings

  the control group, made up of 11 people with no history of epilepsy may have been inappropriate