Localisation of Brain Function

Question 1

Localisation of Function:

Answer 1

The theory that different areas of the brain are responsible for different behaviours, processes or activities.

Question 2

Motor Area:

Answer 2

1. Region in the frontal lobe involved in regulating movement in the opposite side of the body.
2. Damage to this area results of the area may result in the loss of control over fine movements.

Question 3

Somatosensory Area:

Answer 3

1. Parietal lobe that processes sensory information from skin such as touch, heat and pressure.
2. Separated from the motor area by a ‘valley’ called the central sulcus.
3. The amounts of somatosensory area devoted to a particular body part denotes its sensitivity.
4. Receptors in face and hands occupy over half of the somatosensory area.

Question 4

Visual Area:

Answer 4

1. Part of the occipital lobe that receives and processes visual information.
2. Each eye sends information from the right visual field to the left visual cortex. Also, the left visual field and the right visual cortex.
3. Damage to the left hemisphere can produce blindness in part of the right visual field of both eyes.

Question 5

Auditory Area:

Answer 5

1. An area of the temporal lobe of the brain and concerned with the analysis of speech-based information.

Question 6

Broca’s Area:

Answer 6

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

Question 7

Wernicke’s area:

Answer 7

Area of the temporal lobe, encircling the auditory cortex, in the left hemisphere responsible for language comprehension.

Question 8

Hemispheres:

Answer 8

1. Divided into 2 symmetrical halves called left and right hemispheres.
2. Some of our physical and and psychological functions are controlled by a particular hemisphere.
3. This is called lateralisation.
4. Activity on the left-hand side is controlled by the right hemisphere and vice-versa.

Question 9

Cerebal Cortex:

Answer 9

1. Outer layer of both hemispheres and is roughly 3mm thick and appears grey due to the location of cell bodies.
2. Differentiates us from other animals since our cortex is more developed.
3. Responsible for language, memory, reasoning and thought.

Question 10

Paul Broca:

Answer 10

1. In the 1880s, Broca, a surgeon, identified a small area in the left frontal lobe responsible for speech production.
2. Damage to this area causes, Broca’s aphasia, which is characterised by speech that is slow and lacking in fluency.
3. For example, patient Tan.

Question 11

Patient Tan:

Answer 11

1. Discovered this region while treating a patient named Leborgne.
2. Tan was unable to produce any coherent words and could only say Tan, but he could understand spoken language.
3. Broca conducted a post-mortem examination on Tan’s brain and discovered he had a lesion in the left frontal lobe.
4. People with damage to this area experience Broca’s aphasia.

Question 12

Karl Wernicke:

Answer 12

1. Was describing patients who has no problem producing language but severe difficulties understanding it.
2. Meaning their language was fluent but meaningless.
3. Identified a region in the left temporal lobe as being responsible for language comprehension which would result in Wernicke’s aphasia when damaged.
4. They often produce nonsense words- neologisms- as part of the content of their speech.

Question 13

E: Supporting Case Studies

Answer 13

1. Phineas Gage was injured by a blasting rod tore through his prefrontal cortex.
2. The damage caused a defect in rational decision making and the processing of emotion.
3. After the incident he was a surly, aggressive heavy drinker unable to hold down a job. Before he was reported to be a pleasant and hardworking.
4. Shows that some areas of the brain are responsible for specific functions.
5. Case studies, subjectivity of the conclusions drawn, unusual sample and lack of control over confounding and extraneous variables.

Question 14

E: Brain Scans

Answer 14

1. Significant evidence to show that brain functions are localised, especially language and memory.
2. Petersen et al. 1988 used brain scans to demonstrate how Wernicke’s area was active during a listening task and how Broca’s area was active during a reading task.
3. Also, Tulving et al. 1994 revealed that semantic and episodic memories reside in different parts of the prefrontal cortex.

Question 15

E: Link between certain brain areas and symptoms of OCD.

Answer 15

1. Dougherty et al (2002) studied 44 OCD sufferers, who’d undergone a cingulotomy to control their symptoms.
2. Then they were assessed using the Structured Clinical Interview.
3. After a 32 month follow up, 32% met the criteria for treatment response and 14% were partial responders.
4. Shows that certain brain areas were responsible for symptoms of OCD and an improved understanding of localisation has practical applications for more advanced treatments for serious mental disorders.

Question 16

E: Contradictory Theory

Answer 16

1. Holistic function of the brain.
2. Each function requires several brain areas to be activated and that these functions are not restricted to those area.
3. For example, after removing 10-50% of the cortices belonging to rats. They found no specific brain area or lesion was associated with learning how to traverse through a maze.
4. Intelligence or learning is too complex of a cognitive ability to be restricted to certain areas of the brain.

Question 17

E: Plasticity

Answer 17

1. When the brain becomes damaged 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.
2. Lashley describes this as the law of equipotentiality.
3. Does not happen every time, there are several documented cases of stroke victims being able to recover this ability.