A01 Localisation of brain function

• Localisation of function def?

  A) Localisation of Function?

  B) Motor Area?

  C) Somatosensory Area?

  D) Visual Cortex/Area?

  E) Auditory Area?

  F) Broca's Area?

  G) Wernickes's Area

  
• Two theories of the brain:

  • Localised Theory
  • Holistic Theory
• Holistic theory replaced by localisation theory:


  Holistic vs localised brain functioning:

  • LOCALISATION THEORY: Specific areas of the brain were later linked with specific physical & psychological functions.
  • HOLISTIC THEORY: Scientists in the early 19th century supported the holistic theory that ALL PARTS of the brain were involved in processing thoughts and action.
• Localisation theory 



  • Until 19th century was assumed all parts of brain were involved in all elements of action.
  • Specific areas of the brain were later linked with specific physical & psychological functions.
  • If an area of brain damaged through illness/injury, function associated with that area is also affected (damage to a part of the brain would lead to problems in the functioning associated with that specific brain location).
  • Scientists BROCA & WERNICKE argued for localisation theory & said different parts of brain perform different tasks & are involved with different parts of body.
• Holistic Theory?


  • Scientists in the early 19th century supported the holistic theory that ALL PARTS of the brain were involved in processing thoughts and action.
  • NOT HOLISTIC BRAIN FUNCTIONING BUT LOCALISED BRAIN FUNCTION
• 4 MAJOR BRAIN LOBES & 2 OTHER PARTS OF THE BRAIN?

  Frontal Lobe

  Temporal Lobe

  Occipital Lobe

  Parietal Lobe

  Other:

  Brain Stem

  Cerebellum
• Frontal Lobe:


  • Problem solving 
  • Emotional traits 
  • Reasoning (judgement)
  • Speaking 
  • Voluntary motor activity 
  • ‘High cognitive functions’
• Temporal Lobe


  • Hearing (auditory area)
  • Memory 
  • Behaviour 
  • Understanding language
• Brain Stem:


  • Breathing
  • Alertness/speech
  • Body temperature
  • Digestion
  • Swallowing
• Cerebellum


  •  Balance
  • Fine muscle control
  • Coordination & control of voluntary movement
• Parietal Lobe


  • Knowing right from left
  • Sensation 
  • Reading 
  • Body orientation
• Occipital Lobe


  • Vision 
  • Colour perception
• Diagram - Lobes & parts of the brain?

  The cerebellum is the stripped lump under the occipital lobe.

  Spinal cord is the tube clear thing protruding from he temporal & cerebellum

  A) ?

  
•  Who argued for localisation of the brain?

  • Broca 
  • Wernicke
• Areas of the brain?

  ?

  A) ?

  
• Areas/cortex's of the brain?

  • Broca's Area
  • Motor Cortex
  • Somatosensory cortex
  • Visual cortex
  • Wernicke's area
  • Auditory area
• Motor cortex/area 


  • Back of the frontal lobe (in both hemispheres).
  • Controls voluntary movement on the opposite side of the body (lateralized).
  • Damage may result in loss of control over fine muscle/ motor movements (e.g. holding a pen, using cutlery)
• Somatosensory area 


  • Front of both the parietal lobes.
  • Processes sensory information from the skin (touch, heat, pressure etc).
  • The amount of somatosensory area devoted to a particular body part denotes its sensitivity. (more sensitive = more of this area is devoted to it). (this area is separated from the motor area by a ‘valley’ called the central sulcus).
  • FOR EXAMPLE: receptors over our face & hands occupy over half of the somatosensory area.
  • Where sensory info from skin is represented (processes sensory info from the skin - touch, heat, pressure etc).
• Damage to Somatosensory Area?


  • If there is damage to the Somatosensory Cortex = Difficulties identifying objects by touch & also clumsiness due to difficulties perceiving objects handled.
  • Can get numbness/tingling/prickling sensations in certain parts of the body (depending on where damage occurred)
• Visual cortex/area 


  • In occipital lobe at the back of the brain.
  • Function = Each eye sends info from RVF to the left visual cortex, and from the LVF to the right visual cortex.
  • If there is damage to the Visual Cortex = Damage to the left hemisphere could produce blindness in part of the right visual field of both eyes.
• Auditory area


  • In the temporal lobe.
  • Function = Analyses speech-based information.
  • Damage may produce partial hearing loss/deafness - the more extensive the damage, the more serious/extensive the loss.
• Cerebral cortex of both hemispheres is divided into 4 lobes (frontal, parietal, occipital and temporal)
• Cerebral Cortex


  • Outer layer of brain is called the cerebral cortex:
  • The cerebral cortex is like a ‘tea cosy’ covering the inner parts of the brain.
  • It is about 3mm thick
  • Is what separates us from lower animals as it is highly developed.
  • The cortex appears grey due to the location of cell bodies - hence the phrase ‘grey matter’.
  • Cerebral cortex of both hemispheres is divided into 4 lobes (frontal, parietal, occipital and temporal):
• The language Centre - made of?


  The language centre (present only in the left hemisphere)

  Broca's Area

  Wernicke's Area
• Broca’s area


  • In LEFT FRONTAL LOBE
  • Identified by Broca in the 1880s.
  • Responsible for speech PRODUCTION
  • Damage to this area causes Broca’s aphasia which is characterised by speech that is slow, laborious and lacking in fluency ('Tan').
  • Can understand speech & can formulate sentences but struggle to say the sentence.
  • Broca’s patients may have difficulty finding words and naming certain objects.
  • People with Broca’s aphasia have difficulty with prepositions and conjunctions (e.g. ‘a’, ‘the’, ‘and’).
• Wernicke’s area


  • In the left temporal lobe.
  • Identified by Wernicke in the 1880s
  • Responsible for language COMPREHENSION/UNDERSTANDING
  • Damage may affect the ability to comprehend language.
  • People with Wernicke’s aphasia produce language but have severe problems understanding speech, so they produce fluent but meaningless speech (struggle with meaning of words not the speaking). They will often produce nonsense words (neologisms) as part of the content of their speech.
• Brain & lateralisation?


  Brain is divided into 2 halves/hemispheres - the left & right hemispheres and is lateralized:

  • Lateralisation: some physical and psychological functions are controlled by a particular hemisphere.
  • Generally, the left side of the body is controlled by the right hemisphere, the right side of the body by the left hemisphere.
• What do we look at in Localisation of Brain Function?

  • 2 Theories of the brain
  • 4 Lobes & 2 other parts
  • 6 Areas (including language centre)
  • Cerebral Cortex
  • Brain & Lateralisation