Localisation of Function in the brain

• Localisation of Function in the Brain

  During the 19th century, scientists like Broca and Wernicke discovered that specific brain areas are responsible for distinct physical and psychological functions. Previously, the holistic theory held that the entire brain processed thoughts and actions. Their work supported the idea of localisation of function (or cortical specialisation): different brain areas control different body functions, so damage to a specific area affects its associated function.
• Hemispheres of the Brain

  The brain is divided into two symmetrical halves called left and right hemispheres; some of our physical and psychological functions are controlled or dominated by a particular hemispheres
• Cerebral Cortex


  The outer layer of both hemispheres is called the cerebral cortex (or just 'cortex') and it covers the inner parts of the brain; the cortex is about 3mm thick and is far more developed than that of animals. The cortex appears grey due to location of cell bodies.

  
• The lobes of the cortex process specific types of information:

  • Frontal Lobe: Processes information involved in decision making, reasoning, emotion and language.
  • Parietal Lobe: Processes sensory information for temperature, taste and touch.
  • Occipital Lobe: Processes visual information.
  • Temporal Lobe: Processes auditory information.

  
• • Cerebellum: This structure maintains coordination and balance.
  • Brainstem: Controls basic and essential bodily functions such as breathing and heart rate. It also controls the flow of messages from the brain and spinal cord.
• Label this:

  A) frontal lobe

  B) parietal lobe

  C) occipital lobe

  D) cerebellum

  E) temporal lobe

  
• Important Areas within the Lobes

  1. Motor Cortex
  2. Auditory Cortex
  3. Somatosensory Cortex
  4. Visual Cortex
• Motor Cortex


  Found at the back of the frontal lobe and controls voluntary movement in the opposite side of the body. Damage to this area of the brain may result in loss of control over fine movements.

  
• Somatosensory Cortex


  Found at the front of the parietal lobe and separated from the motor area by a valley called the central sulcus. This area processes information from the skin (e.g. heat, pressure, touch) The amount of somatosensory area.

  
• Visual Cortex


  Found in the occipital lobe. Each eye sends information to the visual cortex on the opposite side of the brain. Information from the right visual field is processed by the left visual cortex and vice versa.
• Auditory Cortex


  Found in the temporal lobes and analyse speech based information. Damage to this area would lead to partial hearing loss and a damage to a specific area (Wernicke's area) would lead to difficulty comprehending language.

  
• Language Areas of the Brain

  Unlike the areas above which are found in both hemispheres, language is restricted to the left side of the brain in most people.
• Broca's Area


  Broca's Area is in the motor cortex of the left frontal lobe and is responsible for speech production. Damage to Broca's Area causes Broca's aphasia which is characterised by speech that is slow, laborious and lacking in fluency.
• Wernicke's Area


  Wernicke's Area is in the left temporal lobe (the auditory area) and is responsible for language comprehension.