Localisation of Function in the Brain

Question 1

What is the Frontal Lobe responsible for?

Answer 1

Consciousness, speech production, movement

Question 2

What is the Parietal Lobe responsible for?

Answer 2

Perception

Question 3

What is the Occipital lobe responsible for?

Answer 3

Vision

Question 4

What is the Temporal lobe responsible for?

Answer 4

Speech recognition, hearing

Question 5

What the is the Motor area responsible for?

Answer 5

A region of the frontal lobe involved in regulating movement and outgoing movement

Question 6

What is the Somatosensory area responsible for?

Answer 6

An area of the Parietal lobe that processes sensory incoming information such as touch

Question 7

What is the Visual area responsible for?

Answer 7

A part of the Occipital lobe that receives and processes visual information

Question 8

What is the Auditory area responsible for?

Answer 8

Located in the temporal lobe and concerned with the analysis of speech-based information.

Question 9

Explain the story of Phineas Gage (1848)

Answer 9

• Phineas Gage was the foreman of railway construction gang
• An accidental explosion of a charge he had set blew his tampering iron through his head
• The tampering iron went in point first under his left cheek bone and completely through the top of his head
• He still remained conscious physically recovered

Question 10

What was Phineas Gages personality like before the accident?

Answer 10

• Capable and efficient foreman
• Well-balanced
• Shrewd, smart businessman
• Sociable

Question 11

What was Phineas Gages personality like after the accident?

Answer 11

• Fitful, disrespectful
• Profane
• Impatient and stubborn
• Unable to create and stick to future plans
• His friends said he was “No longer Gage”

Question 12

What is the Motor Cortex responsible for?

Answer 12

Responsible for generation of voluntary motor movements

Question 13

Where is the Motor Cortex located?

Answer 13

Located in the Frontal lobe along the bumpy region, pre-central gyrus

Question 14

What will happen if the Motor Cortex is damaged?

Answer 14

Loss in control over fine movements

Question 15

How is the Motor Cortex arranged?

Answer 15

Logically.

• Different parts of the motor cortex control different parts of the body
• The region that controls the foot is next to the region that controls the leg

Question 16

What is the Somatosensory Cortex responsible for?

Answer 16

Dedicated to the processing of sensory info related to touch; different areas of the body have more receptors than others making them more sensitive such as the skin.

Question 17

Where is the Somatosensory Cortex located?

Answer 17

In Parietal lobe, separated from the motor area by the central sulcus

Question 18

Give an example of Somatosensory Cortex using sensory info

Answer 18

Uses sensory info from skin to produce sensations such as touch pressure, pain, temperature which it then localises specific body regions

Question 19

Explain how sensitivity of the Somatosensory Cortex works

Answer 19

• The amount of somatosensory area devoted to a particular body part denotes its sensitivity.
• For example receptors in our face and hands occupy over half of the somatosensory area.

Question 20

Do both hemispheres have a Somatosensory Cortex and explain?

Answer 20

Yes

The cortex on one side of the brain receives sensory info from the opposite side of the body

Question 21

Where are the Visual centres located?

Answer 21

Visual cortex in the occipital lobe

Question 22

Explain Visual Processing

Answer 22

• It all begins in the retina where light enters and strikes the photoreceptors
• Nerve impulses from the retina then travel to areas of the brain via the optic nerve
• Some travel to areas of the brain involved in coordination of circadian rhythms
• Most terminate in the thalamus, this acts as a relay station passing info to visual cortex
• Each eye sends information from the right visual field to the left visual cortex and from the left visual field to the right visual cortex.
• This means damage to the left hemisphere can produce blindness in the right visual field of both eyes.
• Visual cortex contains different areas that process different types of visual info such as colour, shape and movement.

Question 23

Where are the Auditory Centres located?

Answer 23

In temporal lobes on both sides of the brain

Question 24

Explain the process of hearing

Answer 24

• Begins in cochlea in inner ear, sound waves are converted to nerve impulses
• These travel via the auditory nerve to the auditory cortex
• Then pit stop at the brain stem where basic decoding happens.
• Then in to thalamus which acts as a relay station and carries out further processing of auditory stimulus.
• Last stop is at the auditory cortex
• Sound has already been largely decoded by this point, in the auditory cortex it is recognised and may result in an appropriate response

Question 25

What happens if the Auditory Centres are damaged?

Answer 25

- Damage may produce partial hearing loss; the more extensive the damage, the more extensive the hearing loss

Question 26

Describe and Explain the Case Study of Karl Lashley

Answer 26

- Karl Lashley (1950) conducted an experiment on rats where he removed 10-50% of the rats cerebrum when they were learning their way through a maze. - He found that it didn’t matter which part of the brain was removed, as it was the amount of the brain that was removed which affects the rats ability work their way around the maze, rather than a specific part. - They appeared to need the whole of the cerebrum to complete the task. - He suggested that higher cognitive functions, such as learning, are not localised but distributed holistically in the brain.

Question 27

What is localisation?

Answer 27

The idea that the brain has particular areas that are responsible for specific functions.

Question 28

What is Broca's Area?

Answer 28

An area of the frontal lobe of the brain in the left hemisphere (in most people) responsible for speech production.

Question 29

What is Wernicke's area?

Answer 29

- An area of the temporal lobe (encircling the auditory cortex) in the left hemisphere (in most people) responsible for language comprehension

Question 30

What is Broca's Aphasia?

Answer 30

- Damage to Broca's area - NON-FLUENT aphasia which is trouble with speech production, speech consists of very short and simple sentences, mainly verbs and nouns - Reading and writing are not as effected - Deaf people can sometimes have difficulty signing if Broca's effected

Question 31

Explain (Broca 1865) Case Study

Answer 31

- Broca treated a patient called ‘Tan’ – unable to speak other than this one word (but did understand language) - He studied 8 other patients who had similar language deficits, along with lesions in their left frontal hemisphere - Patients with damage to their right frontal hemisphere did not have the same problems - This lead him to identify the existence of a language centre in the back portion of the frontal lobe of the left hemisphere - Believed to be critical for speech production

Question 32

Evaluation of (Broca 1865) Case Study

Answer 32

- HOWEVER neuroscientist have found that when people perform cognitive tasks (nothing to do with language) their Broca area is active - Fedorenko (2012) discovered 2 regions of Broca’s area – one selectively involved in language, the other involved in responding to many demanding cognitive tasks (such as performing maths problems) - Donkers et al (2007)

Question 33

Explain Donkers et al (2007)

Answer 33

- Dronkers conducted an MRI scan on Tan’s brain, to try to confirm Broca’s findings. - Although there was a lesion found in Broca’s area, they also found evidence to suggest other areas may have contributed to the failure in speech production. - These results suggest that the Broca’s area may not be the only region responsible for speech production and the deficits found in patients with Broca’s aphasia could be the result of damage to other neighbouring regions

Question 34

What is Wernicke's Aphasia?

Answer 34

- Damage to Wernike’s area - FLUENT aphasia which is trouble with speech comprehension. Also can’t produce meaningful sentences, can string words together but what they saw is nonsensical.

Question 35

Explain Wernicke

Answer 35

- Wernicke identified patients who had no problem pronouncing language but severe difficulties understanding it - He identified an area in the temporal lobe as being responsible for language comprehension - Patients who have Wernicke’s aphasia would often produce nonsense words Neologism as part of the content of their speech. - He proposed that language involves separate motor and sensory regions located in different cortical regions. - The motor region, located in Broca’s area, is close to the area that controls the mouth, tongue and vocal cords. - The sensory region, located in Wernicke’s area, is close to regions of the brain responsible for auditory and visual input. - Input from these regions is thought to be transferred to Wernicke’s area where it is recognised as language and associated with meaning. - There is a neural loop running between Broca’s area and Wernicke’s area. At one end lies Broca’s area, responsible for the production of language, and at the other lies Wernicke’s area, responsible for the processing of spoken language

Question 36

Evaluation to Wernicke

Answer 36

- Herasty (1997) - Turk et al (2002)

Question 37

Explain Herasty (1997)

Answer 37

- Found that women have proportionally larger Broca’s and Wernicke’s areas than men, which can perhaps explain the greater ease of language use amongst women. - This, however, suggests a level of beta bias in the theory: the differences between men and woman are ignored, and variations in the pattern of activation and the size of areas observed during various language activities are not considered.

Question 38

Explain Turk et al (2002)

Answer 38

- Discovered a patient JW, who suffered damage to the left hemisphere but developed the capacity to speak in the right hemisphere, eventually leading to the ability to speak about the information presented to either side of the brain. - This suggests that perhaps localisation is not fixed and that the brain can adapt following damage to certain areas.