Localisation of function and hemispheric lateralisation

• The motor areas of the brain controls voluntary movement and is located in the frontal lobe.
• The hippocampus orchestrates memory consolidation
• Somatosensory Cortex:

  • Located in the parietal lobe.
  • Processes sensory information from the skin (e.g., touch, pressure, pain, and temperature).
• Visual Cortex:

  • Located in the occipital lobe.
  • Processes visual information, with each hemisphere receiving input from the opposite visual field.
• Auditory Cortex:

  • Located in the temporal lobe.
  • Processes auditory information, such as sound and speech.
• Broca’s Area: Found in the left frontal lobe; responsible for speech production.
• Wernicke’s Area: Found in the left temporal lobe; responsible for language comprehension.
• Cortical specialisation refers to the idea that different areas of the brain are responsible for specific functions and behaviours. This concept is also referred to as localisation of function.
• Damage to the Broca's area can cause Broca’s aphasia, which results in difficulty speaking but intact comprehension.

  • Studied a patient known as "Tan", who could only say the word "tan" but could understand spoken language.
  • Post-mortem examination revealed damage to a specific area in the left frontal lobe (now called Broca’s area).
• Damage to Wernicke's area can result in Wernicke’s aphasia, where speech is fluent but lacks meaning.

  • Investigated patients who could speak fluently but produced meaningless speech and had difficulty understanding language.
  • Found damage to the left temporal lobe (now called Wernicke’s area).
• Phineas Gage had damage to the frontal lobe which resulted in personality changes, as he became more aggressive, and impulsive and struggled with planning and social interactions.

  • This demonstrated that the frontal lobe controls personality, decision-making and emotional regulation.
• HM has parts of his hippocampus removed, he lost his ability to form new memories.

  • This suggests the hippocampus is critical for memory formation as he could no longer form new long-term memories.
• Outline the difference in function between Broca's area and Wernicke's area (2)

  • Broca’s area is responsible for speech production whereas Wernicke’s area is responsible for language comprehension.
  • Broca’s area enables speech to be fluent whereas Wernicke’s area enables speech to be meaningful.
• A = Broca’s area

  B = Motor cortex

  C = Somatosensory cortex

  D = Visual cortex

  E = Wernicke’s area

  
• A = Somatosensory cortex

  B = Visual cortex

  C = Auditory cortex

  
• The left hemisphere is responsible for speech production (via Broca’s area) and language comprehension (via Wernicke’s area), as well as logical reasoning.
• The right hemisphere is responsible for spatial awareness, emotion recognition and creativity.
• Hemispheric lateralisation refers to the idea that certain mental processes and functions are predominantly controlled by one hemisphere of the brain rather than being equally distributed across both hemispheres.
• Contralateral control refers to the idea that each hemisphere controls the opposite side of the body.

  • The left hemisphere controls the right side of the body.
  • The right hemisphere controls the left side of the body.