Localisation and Lateralisation

Question 1

What is localisation of function?

Answer 1

The idea that certain functions (e.g. language, memory etc) have certain locations within the brain.

Question 2

Describe the case of Phineas Gage

Answer 2

• Phineas gage was working on a rail line in 1848. During an accident a piece of iron went through his skull
• He survived the accident but experienced a personality change such as anger and loss of inhibition.

Question 3

Why is the case of Phineas Gage helpful?

Answer 3

It provides support for localisation of brain function because the area that the iron bar went through was responsible for personality.

Question 4

What are the 4 key areas of the brain for localisation?

Answer 4

Motor Area
Somatosensory Area
Visual Area
Auditory Area

Question 5

Describe the motor area

Answer 5

• Located in the frontal lobe
• Responsible for voluntary movements by sending signals to the muscles in the body.

Question 6

Describe the somatosensory area

Answer 6

• Located in the parietal lobe
• Receives sensory information from the skin to produce sensations related to pressure, pain, temperature etc.
• Different parts of the somatosensory area receive messages from different locations of the body.

Question 7

Describe the visual area

Answer 7

• Located at the back of the brain in the occipital lobe.
• Receives and processes visual information
• Information from the right-hand side visual field is processed in the left hemisphere, and information from the left-hand side visual field is processed in the right hemisphere.
• The visual area contains different parts that process different types of information including colour, shape or movement.

Question 8

Describe the auditory area

Answer 8

• Located in the temporal lobe
• Responsible for analysing and processing acoustic information.
• Information from the left ear goes primarily to the right hemisphere and information from the right ear goes primarily to the left hemisphere.
• The primary auditory area is involved in processing simple features of sound including volume, tempo and pitch.

Question 9

What are the two language centres in the brain?

Answer 9

The Broca’s area and Wernicke’s area

Question 10

Describe the broca’s area

Answer 10

• Motor region is located here.
• Located in the left frontal lobe.
• Responsible for speech production.

Question 11

What results in damage to the broca’s area?

Answer 11

They can experience Broca’s aphasia which results in slow and inarticulate speech.

Question 12

Describe Wernicke’s area

Answer 12

• Sensory region is located here.
• Located in the left temporal lobe.
• Responsible for understanding languages.

Question 13

What results in damage to the Wernicke’s area?

Answer 13

They can experience Wernicke’s aphasia and struggle to comprehend language and often produce sentences that are fluent but meaningless.

Question 14

Evaluate the localisation of function

Answer 14

• The claim that functions are localised to certain areas of the brain has been criticised. Lashley proposed the equipotentiality theory which suggests that basic motor and sensory functions are localised, but higher mental functions are not. He claimed intact areas of the cortex could take over responsibility for specific cognitive functions following a brain injury. This suggests that functions are not localised to just one region, as other regions can take over specific functions following a brain injury.
• Some psychologists argue that the idea of localisation fails to take into account individual differences. Herasty (1997) found that women have larger Broca’s and Wernicke’s areas than men. This suggests a level of beta bias in the theory, the differences of men and women are ignored.

Question 15

What is hemispheric lateralisation?

Answer 15

The idea that the two halves of the brain are functionally different and that each hemisphere has specialisations

Question 16

What is the left hemisphere and right hemisphere dominant for?

Answer 16

Left: dominant for language
Right: Visual motor tasks

Question 17

How are the two hemispheres connected?

Answer 17

Through nerve fibres called the corpus callosum

Question 18

Explain split-brain research

Answer 18

Sperry and Gazzaniga (1967)
Aim: To examine the extent the two hemispheres are specialised for certain functions.

Method: An image or word is projected to the patients left visual field which is processed by the right hemisphere or the right visual field which is processed by the left hemisphere. When information is presented to one hemisphere in a split-brain patient, the information is not transferred to the other hemisphere since the corpus callosum is cut.

NOT COMPLETED

Question 19

What is brain plasticity?

Answer 19

Refers to the brain’s ability to change and adapt because of experiences.

Question 20

What is functional recovery and how does the brain do this?

Answer 20

The transfer of functions from a damaged area of the brain after trauma to other undamaged areas.

The brain does this through a process called ‘neuronal unmasking’ where ‘dormant’ synapses (synapses that have not received enough input to be active) open connections to compensate for a nearby damaged area of the brain. This allows new connections in the brain to be activated, thus recovering any damage in specific regions.

Question 21

Evaluate brain plasticity

Answer 21

Kuhn et al. found an increase in grey matter in various regions of the brain after participants played video games for 30 minutes a day over a two-month period. Davidson et al showed the permanent change in the brain generated by prolonged meditation. Buddhist monks who meditated frequently had a much greater activation of gamma waves (which coordinate neural activity) than did student with no experience of meditation. These two studies support the idea of plasticity and the brain’s ability to adapt from new experiences whether it’s video games or meditation.