Biopsychology - Localisation of function

Question 1

What is localisaton of function?

Answer 1

Functions such as movement, speech and memory are performed in distinct regions of the brain.

Question 2

What functionally specialised brain areas are found on both sides of the brain?

Answer 2

Motor, somatosensory, visual and auditory cortices

Question 3

What areas of the brain are only found on the left hemisphere?

Answer 3

Broca and Wernicke’s area (hemispherically lateralised)

Question 4

Define hemispheric lateralisation

Answer 4

Each hemisphere of the brain (right/left) is specialised to perform different functions. (language centers are in the left hemisphere, visuospatial tasks are best performed by the right)

Question 5

Define contralateral

Answer 5

Each hemisphere of the brain controls the opposite side of the body. Including both motor and sensory pathways and vision of the contralateral visual field

Question 6

Define ‘cortex’

Answer 6

Surface layer of the brain referred to as grey matter, 2-4mm thick and folded for extra surface area for processing

Question 7

What is the function of the occipital lobe?

Answer 7

The brains visual processing center, each hemispheres occipital lobe receives information from the contralateral visual field

Question 8

What does damage in the occipital lobe lead to?

Answer 8

Leads to partial or complete loss of vision called cortical blindness. Damage to one cortex can lead to a loss of vision in the opposite visual field.

Question 9

Where can the motor and somatosensory cortex be found? What divides them?

Answer 9

Motor cortex is at the back of the frontal lobe and the somatosensory cortex is at the front of the parietal. They are divided by a fold called the central sulcus and are contralateral

Question 10

What is the motor cortex?

Answer 10

Area of the brain responsible for voluntary motor movements (e.g deciding to move your arm). Contralateral.

Question 11

What does damage in the motor cortex result in?

Answer 11

Loss of muscle function or after severe trauma, paralysis. This occurs on the opposite side of the body to the damage due to contralaterality

Question 12

What is the function of the somatosensory cortex?

Answer 12

Area of the brain responsible for receiving sense impressions from around the body. Contralateral

Question 13

What does damage in the somatosensory cortex lead to?

Answer 13

Loss of sensation, ignoring areas of the body, loss of ability in recognising objects by their touch (agnosia). Effects are in opposite side to damage.

Question 14

Auditory cortex function and location

Answer 14

Receives and processes sound information from ears. Located in both hemisphere, located at the top of the temporal lobe

Question 15

Broca’s area function and location

Answer 15

Located in the left frontal lobe, Broca’s area is responsible for speech production. Discovered after case study and post mortem of Tan whon.

Question 16

Damaged Broca’s Area effect

Answer 16

Broca’s aphasia - difficulty producing fluent speech, speech is slow and effortful. Speech has missing words leading to poor grammar

Question 16

Damaged Broca’s Area effect

Answer 16

Broca’s aphasia - difficulty producing fluent speech, speech is slow and effortful. Speech has missing words leading to poor grammar

Question 17

Wernicke’s Area location and function

Answer 17

Located in the top temporal lobe, responsible for speech comprehension. Discovered after case studies of individuals who could produce fluent sounding speech but could not understand others.

Question 18

Damaged Wernicke’s Area effects

Answer 18

Wernicke’s aphasia - difficult understanding speech or written language, speech sounds fluent but lacks meaning/ nonsense words.

Question 18

Damaged Wernicke’s Area effects

Answer 18

Wernicke’s aphasia - difficult understanding speech or written language, speech sounds fluent but lacks meaning/ nonsense words.

Question 19

Global aphasia

Answer 19

Damage to both Broca’s and Wernicke’s area can lead to global aphasia, the inability to produce or understand speech

Question 20

Strengths of Localisation of function

Answer 20

+ Clinical case study research demonstrates loss of certain functions if damage is caused to particular ares of the brain e,g broca and wernicke’s case studies (Aphasia) . Suggests localisation.

+ Modern brain scanning techniques like fMRI support older research on language centres, showing activation in the regions associated when healthy participants perform language tasks

Question 21

Limitations of lof

Answer 21

• Use of case studies are seen as unscientific, especially in brain research with damage often covering multiple regions as see when modern MRI scans were made of Tan’s brain.
• Some functions, like consciousness appear not to be localised at all. Suggesting the correct approach in arguing for localised or holistic nature of the brain depends on the function. Also due to the high connectivity of the brain no one area is independent.
• Lashley Rat study = 50 rats ran a maze before their brain cortex was destroyed . Found ability to re-run the maze was affected by how much brain cortex was destroyed not which areas. Suggests higher cognitive processes such as learning and memory are not localised but are distributed. Also equipotentiality of the cortex, any healthy area of the cortex can perform the memory functions of damaged areas.