Localisation of Function in the Brain

Question 1

What does localisation of function refer to?

Answer 1

The principle that specific areas of the brain have specific functions.

Question 2

What are the internal areas of the brain covered by?

Answer 2

A 3mm outer layer called the cerebral cortex which is divided up & named according to its function.

Question 3

How many hemispheres does our brain have?

Answer 3

2-right hemisphere & the left hemisphere.

Question 4

Name the the 4 lobes in the brain.

Answer 4

• Frontal lobe
• Temporal lobe
• Parietal lobe
• Occipital lobe

Question 5

What is the motor cortex?

Answer 5

• Location: frontal lobe.
• Function: controls voluntary movements by sending signals to the muscles in the body.
• Hemisphere: both: the motor cortex of each hemisphere controls the muscles on the opposite side of the body.

Question 6

What is the somatosensory cortex?

Answer 6

• Location: parietal lobe.
• Function: receives incoming sensory info from the skin to produce sensations related to pressure, pain, temp, etc.
• Hemisphere: both: the somatosensory cortex of each hemisphere receives info from the opposite side of the body.

Question 7

What is the visual cortex?

Answer 7

• Location: occipital lobe.
• Function: receives & processes visual info and contains different parts that process different types of info incl. colour, shape & movement.
• Hemisphere: both: info from the right visual field is processed in the visual cortex of the left hemisphere & vice versa.

Question 8

What is the auditory cortex?

Answer 8

• Localisation: temporal lobe.
• Function: receives & processes acoustic info and enables auditory stimuli to be identified & spatially located.
• Hemisphere: both: info from the left ear goes primarily to the right hemisphere & vice versa.

Question 9

What is Broca’s area?

Answer 9

• Location: left frontal lobe.
• Function: responsible for speech production & damage leads to production aphasia, which involves difficulties formulating speech.
• Hemisphere: lateralised to the left.

Question 10

What is Wernicke’s area?

Answer 10

• Location: left temporal lobe.
• Function: responsible for the interpretation of speech & damage leads to receptive aphasia, which involves difficulties understanding speech.
• Hemisphere: lateralised to the left.

Question 11

Evaluation of Research into Localisation of Function in the Brain.

Answer 11

• Pioneering evidence supporting localised brain functions: Broca (1865): case study on Louis Leborgne (aka ‘Tan’).
• Case study of Phineas Gage (1948) also supports the idea of localised brain function: frontal lobe is responsible for regulating mood & not essential bodily functions.
• Evidence refuting localised brain function: Lashley (1950): he removed 10-50% of the cortex in rats that were learning a maze: it was found that no single area was more important than another in terms of the rats’ ability to learn the maze: equipotentiality.
• A methodological issue of neuropsychological research into localisation of function in humans: over reliance on post-mortem case studies of brain-damaged patients. Very small numbers of ps are used in this way as it would be unethical to purposefully damage the brain in a living person. However, such studies lack population validity-indivdual differences.