Lesson 6 - Localisation of Function

Question 1

Brain’s Visual Centres

Answer 1

• Visual cortex process info such as colour and shape
• In the occipital lobe of both hemispheres
• Visual processing starts in the retina where light enters and strikes the photoreceptors
• Nerve impulses from the retina are transmitted to the brain via the optic nerves
• Most terminate in the thalamus, which acts as a relay station, passing the info onto the visual cortex

Question 2

Brain’s Auditory Centres

Answer 2

• Processes information such as pitch and volume
• Lies in the temporal lobe in both hemispheres
• Pathway begins in the cochlea of the inner ear, where sounds waves are converted to nerve impulses
• Which travel via the auditory nerve to the auditory cortex
• Basic decoding occurs in the brain stem
• The thalamus carries out further processing before impulses reach the auditory cortex

Question 3

Motor Cortex

Answer 3

• Responsible for voluntary movements
• Located in the frontal lobe of both brain hemispheres
• Different parts of the motor cortex control different parts of the body
• Damage to this area can cause a loss of muscle function or paralysis in one or both sides of the body

Question 4

Somatosensory Cortex

Answer 4

• Responsible for sensations such as pain and pressure

- Located in the parietal lobe of both hemispheres

Question 5

Broca’s Area

Answer 5

• Speech production
• Frontal lobe of left hemisphere
• Damage leads to expressive aphasia

Question 6

Expressive Aphasia

Answer 6

• Affects language production but not understanding
• Speech lacks fluency and patients have difficulty with certain words which help sentences function
• Such as ‘it’ and ‘the’

Question 7

Wernicke’s Area

Answer 7

• Understanding of speech
• Left hemisphere of temporal lobe
• Connected to Broca’s area by a neural loop
• Damage to Wernicke’s area leads to receptive aphasia

Question 8

Receptive Aphasia

Answer 8

Leads to an impaired ability to understand language

Question 9

More locality AO3

Answer 9

• Some functions are more localised
• Motor and somatosensory functions are highly localised to specific areas of the cortex
• Higher functions (personality) are much more widely distributed
• Functions such as language are too complex to be assigned to just one area and instead involve networks of brain regions

Question 10

Equipoteniality Theory (Lashley 1930) AO3

Answer 10

• Higher mental functions are not localised
• Claims that intact areas of the context take over responsibility for a specific cognitive function following injury to the area normally responsible

Question 11

Brain Communication (Dejerine 1892) AO3

Answer 11

• Brain communication may be more important than specific brain regions
• Reported a patient who could not read because of damage between the visual cortex and Wernicke’s Area

Question 12

Preserved Brains (Dronkers et al 2007) AO3

Answer 12

• 2 of Broca’s patients’ preserved brains examined
• MRI scans revealed that several areas of the brain had been damaged
• Lesions to the Broca’s Area cause temporary speech disruption they do not usually result in severe disruption of language
• Language is more widely distributed than originally thought

Question 13

Individual Differences (Bavalier et al 1997) AO3

Answer 13

• Individual Differences in which brain areas are responsible for certain functions
• Found that different brain areas are activated when a person is engaged in silent reading
• Observed activity in the right temporal lobe, left frontal lobe and occipital lobe
• Meaning that the function of silent reading does not have a specific location in the brain