localisation of function in the brain

Question 1

What is the motor cortex?

Answer 1

A region of the frontal lobe involved in regulating voluntary movement.

Question 2

What is the somatosensory cortex?

Answer 2

An area of the parietal lobe that processes sensory information such as touch.

Question 3

What is the visual cortex?

Answer 3

A part of the occipital lobe that receives and processes visual information.

Question 4

What is the auditory cortex?

Answer 4

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

Question 5

What is Broca’s area?

Answer 5

An area of the frontal lobe of the brain in the left hemisphere responsible for speech production.

Question 6

What is Wernicke’s area?

Answer 6

An area of the temporal lobe in the left hemisphere responsible for language comprehension.

Question 7

Outline localisation of the brain theory.

Answer 7

Prior to scientific research into the brain, psychologists supported a holistic view of the brain.
Recent research has concluded that specific areas of the brain have specific functions associated with them.
Paul Broca was the first person to use deficit in function to attribute different functions to particular areas of the brain.

Question 8

The brain is divided into two symmetrical halves, what are they called?

Answer 8

left and right hemisphere.

Question 9

What is the name of the outer layer of both hemispheres?

Answer 9

cerebral cortex.

Question 10

Describe how the two hemispheres differ in their functions?

Answer 10

Some functions are dominated by one hemisphere (lateralisation).
Activity on the left side of body is controlled by right hemisphere and vice versa.

Question 11

What areas of the brain are localised? (5)

Answer 11

visual centres.
auditory centres.
motor cortex.
somatosensory cortex.
language centres.

Question 12

The cortex of both hemispheres is sub-divided into four lobes, what are these lobes called?

Answer 12

frontal lobe.
parietal lobe.
occipital lobe (visual cortex)
temporal lobe.

Question 13

Which area of the brain process vision?

Answer 13

The occipital lobes.

Question 14

Describe the function of the occipital lobe.

Answer 14

The visual area at the back of the brain.
Each eye sends info from the right visual field to the left visual cortex and vise versa.
Means that damage to the occipital lobe in the left hemisphere would cause blindness in the right visual fields of each eye.

Question 15

Which area of the brain processes sound?

Answer 15

The temporal lobes.

Question 16

Describe the function of the temporal lobes.

Answer 16

Process auditory info.
Allows us to perceive sounds in the environment.
Signals are sent from the auditory cortex to other parts of the brain to process high level info.
For example, Wernicke’s area to understand language comprehension.

Question 17

Which area of the brain processes motor movement?

Answer 17

The motor cortex.

Question 18

Describe the motor cortex.

Answer 18

Sits at the back of the frontal lobe in both hemispheres.
Controls voluntary behaviour.
Similar to the visual cortex, the motor cortex in the left hemisphere processes movement of the right side of the body and visa versa.
Damage to this area of the brain would result in a loss of control of fine movements.

Question 19

Which area of the brain processes sensory information?

Answer 19

The somatosensory cortex.

Question 20

Describe the function of the somatosensory cortex.

Answer 20

Processes sensory info from the body e.g. heat, pressure, touch.
This area is present in both of the hemispheres at the front of the parietal lobes and is separated from the motor cortex by the brains central sulcus.
The amount of somatosensory area devoted to each area of the body denotes its sensitivity, e.g. receptors in our face and hands occupy over half of the somatosensory area.

Question 21

Which area of the brain processes language?

Answer 21

Language is processed only in the left hemisphere.
Broca found an area responsible for speech production = Broca’s area.
Damage causes aphasia - slow, laborious speech that lacks fluency (case study = Tan).
However Wernicke researched into patients who could speak fine but lacked the ability to understand and comprehend speech.
Language they produced was fluent but meaningless.
Found an area responsible for language comprehension = Wernicke’s area.

Question 22

Discuss brain scan evidence as a strength of localisation of function in the brain.

Answer 22

Petersen et al (1988).
Used PET scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task.
Suggests these areas of the brain have different functions, supporting the validity of localisation of function.
Brain scans provide strong evidence due to their objectivity, and their results can be observed by other researchers.
Similarly, a study of long-term memory by Tulving et al (1994) revealed that semantic and episodic memories reside in different parts of the prefrontal cortex.
This further supports the validity of the theory.

Question 23

Discuss neurosurgical evidence as a strength of localisation of function in the brain.

Answer 23

Dougherty et al (2002).
Reported on 44 people with OCD who had undergone a cingulotomy - a neurosurgical procedure that involves lesioning of the cingulate gyrus.
At post-surgical follow-up, a third had met the criteria for successful response to the surgery and 14% for partial response.
The success of procedures such as this strongly suggest that symptoms and behaviours associated with serious mental disorders are localised.

Question 24

Discuss the research of Lashley (1950) as a limitation of localisation of function in the brain.

Answer 24

Suggests higher cognitive functions, such as the processes involved in learning, are not localised but distributed in a more holistic way in the brain.
Lashley removed areas of the cortex of rats that were learning a maze.
No area was proven to be more important than any other area in terms of the rats ability to learn the maze.
The process of learning appeared to require every part of the cortex, rather than being confined to a particular area.
This suggests that learning is too complex to be localised and therefore limits the validity of localisation of function in the brain.
We should however be cautious in drawing conclusions related to the human being from this study due to the use of animals, as we do differ slightly in how our brains function.

Question 25

Discuss plasticity as a limitation of localisation of function in the brain.

Answer 25

When the brain has become damaged through an illness or accident, and a particular function has been compromised or lost, the rest of the brain appears able to reorganise itself in an attempt to recover the lost function.
Lashley described this as equipotentiality.
Although this doesn’t happen every time, there are several documented cases of stroke victims being able to recover those abilities that were seemingly lost as a result of the illness.
This apparent plasticity of the brain lends support to holistic rather than localisation theory, and limits localisation theory in suggesting that function of the brain is more complex than the theory proposes.

Question 26

discuss reductionism as a limitation of localisation.

Answer 26

critics argue that theories of localisation are biologically reductionist in nature and try to reduce very complex human behaviours and cognitive processes to one specific brain region. Such critics suggest that a more thorough understanding of the brain is required to truly understand complex cognitive processes like language.

Question 27

discuss gender differences as a limitation of localisation.

Answer 27

Finally, some psychologists argue that the idea of localisation fails to take into account individual differences. it has been 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.