LOCALISATION OF FUNCTION REVISION

STUDENT REVISION BOOKLET:

·      MODULE: Biopsychology (AS Level)

·      TOPIC: Localisation of Function

·      EXAM BOARD: AQA

AQA SPECIFICATION (RELEVANT SECTION)

Localisation of function in the brain and hemispheric lateralisation: motor, somatosensory, visual, auditory and language centres; Broca’s and Wernicke’s areas

LEARNING OBJECTIVES:

• Recall and label brain areas responsible for key functions.

• Understand typical research methods used in this area.

• Evaluate strengths and limitations of the localisation of function theory.

• Apply understanding to short-answer and essay-style exam questions.

STARTER: CHALK & TALK – BRAINSTORM LOCALISATION

Name the four lobes of the brain."

"Now point to each of them on your own head. Let’s activate your brain about the brain."

Next — we’re going to brainstorm as many words as you can think of that link to the topic of localisation. Hands up, call them out — key terms, areas, anything you remember."

Why are we brainstorming words for localisation?"

1. Because it acts as a retrieval cue — when you start listing things, it jogs other memories linked to the same schema. This helps you access things you do know but might otherwise forget.

2. Because it helps with essay writing — it forces you to be systematic, so you don’t leave out important AO1 or AO3 points in a 16-marker.

TASK 5: AO2 & AO3 MULTIPLE CHOICE QUESTIONS – LOCALISATION OF FUNCTION

1. A patient loses the ability to speak after a stroke damages Broca’s area but regains speech after physiotherapy. What does this suggest about the localisation of function?
A. Broca’s area is not involved in speech after all
B. Speech is never localised and is processed across the whole brain
C. Localisation exists, but the brain can redistribute functions when damaged
D. Language recovery is due to memory compensating for lost speech pathways

2. AQA examiners report that students often overuse Phineas Gage to support localisation. Why is this a weak AO3 point?
A. He had damage to subcortical structures, not cortical ones
B. The case was misreported and discredited
C. His injury was not in any region listed on the AQA specification
D. His language was severely affected, which contradicts the theory

3. According to evolutionary theory, why do many species, including humans, show localisation of brain function?
A. Specialised modules were naturally selected because they improved the speed and efficiency of adaptive behaviours
B. Localisation evolved to prevent duplication of brain regions across hemispheres
C. Localisation became fixed because it reduced metabolic demand in neural pathways
D. Species with diffuse brain organisation were less able to respond to environmental challenges

4. fMRI activates Broca’s area and other frontal and temporal regions during a speech task. What does this suggest about how the brain functions and is organised?
A. Broca’s area only activates when the task involves writing, not speech
B. Activation in other areas likely reflects random noise in brain scans
C. Brain functions, such as speech, may be supported by broader interacting networks
D. The scanner misattributed hearing to speech output

5. Research shows that many left-handed people process language in non-typical brain areas. What issue does this raise for localisation theory?
A. Left-handers rely on the cerebellum for speech
B. Localisation may not apply in the same way to all individuals
C. Language in left-handers is processed through subcortical structures
D. Only right-handers exhibit accurate localisation.

6. In a study comparing language regions in men and women, researchers found that women have significantly larger volumes in Broca’s and Wernicke’s areas. What bias might the standard localisation theory be criticised for?
A. Alpha bias – overestimating female advantage in language
B. Beta bias – assuming structural differences don’t affect function
C. Selection bias – ignoring right-hemisphere involvement
D. Measurement bias – failing to control for skull size in MRI scans

· 7. How has the theory of localisation of function contributed to real-world clinical practice?
A. It enables clinicians to link specific cognitive deficits to areas of damage, guiding targeted rehabilitation
B. It proves why some people are left-brained and others right-brained
C. It has allowed doctors to reverse language loss through hemisphere switching
D. It explains why people recover faster when brain lesions occur bilaterally

8. In a study comparing language regions in men and women, researchers found that women have significantly larger volumes in Broca’s and Wernicke’s areas. What bias might the standard localisation theory be criticised for?
A. Alpha bias – exaggerating sex differences
B. Beta bias – minimising sex differences
C. Androcentrism – focusing only on male data
D. Selection bias – using only bilingual speakers?

TYPICAL EXAMINATION QUESTIONS

1.     Studies have identified Broca’s and Wernicke’s areas responsible for language. Outline the difference in function between Broca’s area and Wernicke’s area. (2 marks) A01.

2.     Discuss what research has shown about the localisation of function in the brain. (8 marks) A01 AND A03

3.     Lotta’s grandmother suffered a stroke to the left hemisphere, damaging Broca’s area and the motor cortex. Using your knowledge of the functions of Broca’s area and the motor cortex, describe the problems that Lotta’s grandmother is likely to experience. (4 marks) A02

4.     Lotta worries that she will be unable to recover because of her grandmother’s age. Using your knowledge of plasticity and functional recovery of the brain after trauma, explain why Lotta might be wrong. (8 marks) A02

5.     Discuss localisation of function in the brain. (16 marks) A01 and A03

EXAMINER FEEDBACK

✔️ High-level responses:

• Students described specific brain areas and their functions accurately.

• Used relevant case studies and research linked directly to localisation (not just lateralisation)

• Evaluated by discussing how well the evidence supports the theory.

❌ Common mistakes:

• Using Phineas Gage as evidence for localisation (his case does not map to the areas named in the spec)

• Describing split-brain research without linking to localisation

• Generic evaluation is not applied to localisation theory.

TASK 6: HOW TO WRITE A 6-MARK AO1 ANSWER ON LOCALISATION OF FUNCTION

This is a "describe" question, so you must explain clearly and factually. No evaluation. Structure matters.

1. Define localisation of function.
Explain what it is – the idea that specific areas of the brain control specific functions.

2. Give historical background.
Mention the origin of the theory (e.g. phrenology), and contrast it with older ideas like equipotentiality, which said the brain acted as a whole.

3. Name and describe at least three localised brain areas.
You must say:

• What each area does (its function)

• Where in the brain is it located (which lobe or hemisphere)

• Include hemispheric lateralisation (left and right sides) and contralateral control (left controls right, and vice versa).

MODEL AO1 ANSWER (6 MARKS)

Localisation of function is the theory that different brain areas are responsible for particular psychological or physiological functions. According to this view, specific regions of the cerebral cortex control specific processes such as movement, sensation, vision, hearing, or language. It is hypothesised that when a particular brain area is damaged, the function associated with it is typically lost or impaired.

The modern theory of localisation was developed in the 19th century. At the time, scientists were commissioned to test the claims of phrenology, a theory that linked skull shape to personality traits. Although phrenology was disproven, testing it led to the discovery that damage to specific brain areas produced consistent functional losses, supporting the idea that functions may be localised.

Several areas of the cortex are associated with distinct roles. For example, the motor cortex controls voluntary movement at the back of the frontal lobe. In the parietal lobe, the somatosensory cortex processes sensory input from the skin. The visual cortex, located in the occipital lobe, processes visual information, and the auditory cortex, in the temporal lobe, is involved in hearing.

Language functions are also thought to be localised: a region in the frontal lobe is associated with speech production, while an area in the temporal lobe is linked to language comprehension.

The brain is divided into two hemispheres, and many functions are contralateral, meaning each hemisphere controls the opposite side of the body. Some functions, such as language, are also lateralised, being dominant in one hemisphere.

TASK 7: HOW TO STRUCTURE AO3 FOR LOCALISATION OF FUNCTION (10 MARKS )

You are being assessed on how well you evaluate the theory. This means weighing up the strength of evidence, considering alternative explanations, and showing insight into real-world and theoretical implications.

STEP 1: START WITH RESEARCH SUPPORT

Instruction: Always begin with research evidence. Start with weaker or limited methods, then build to more credible support. Show that your evaluation is layered.

a. Case Studies (Weak – Individual Differences Limit Generalisability)
e.g. Broca’s patient “Tan” showed speech loss and damage to the left frontal lobe. However, it’s just one individual. His brain may have had atypical organisation, and the evidence is from a post-mortem, not live brain activity.

b. Animal Studies (Weak – Poor Generalisability)
Ablation research (e.g., Lashley) showed that some functions, like memory, are not strictly localised, especially in rats. However, applying animal results to human cognition is methodologically limited, especially for uniquely human faculties like language.

c. Electrical Stimulation (Moderate – Controlled but Invasive)
Penfield’s neurosurgical stimulation of live patients revealed mapped motor and sensory cortices, strongly supporting localisation. But these are rare and often involve clinical populations, not healthy brains.

d. Brain Imaging (Strongest – Live, Objective, Large Samples)
fmri and PET scans provide the most substantial evidence: they show real-time brain activity in living humans, with consistent activation of Broca’s and Wernicke’s areas during speech and comprehension tasks.

Triangulation: This shows how multiple methods (post-mortems, stimulation, scanning) converge on similar findings, strengthening the claim of localisation.

STEP 2: ADD NUANCE – LOCALISATION ISN’T 100% UNIVERSAL

Instruction: Show the limitations of strict localisation. Use individual differences.

• Left-Handers: ~40% of left-handers show non-typical language lateralisation. Some use the right hemisphere, or even both. This means localisation patterns vary.

• Gender Differences: Studies (e.g. Pearlson) found larger language areas in women, suggesting sex differences in localisation. Most early research used male brains, leading to possible beta bias.

• Brain Damage Recovery: After strokes, language function can return as other brain areas compensate, demonstrating functional plasticity, not rigid localisation.

STEP 3: THEORETICAL CHALLENGE – DISTRIBUTED PROCESSING

Instruction: Now, show that some behaviours require multiple areas to work together.

• Fedorenko (2012) found that Broca’s area is activated during language and non-verbal problem-solving.

• Cognitive functions like language and memory often involve networks, not isolated centres.

• The distributed model argues that the brain is modular, but modules interact — localisation is real, but not absolute.

STEP 4: WHY WOULD THE BRAIN BE ORGANISED THIS WAY?

Instruction: Briefly justify why localisation makes evolutionary sense.

• From an evolutionary perspective, having specialised modules would increase efficiency.

• For example, language areas likely developed due to group hunting, social bonding, or coordination.

• Localisation allows for faster, more reliable processing of critical tasks (e.g. vision, movement, language).

STEP 5: REAL-WORLD APPLICATION

Instruction: Show how the theory is helpful beyond academia.

• In neurosurgery, surgeons avoid damaging localised areas during tumour removal.

• Understanding which areas control which functions in stroke rehab helps design targeted therapies.

• In neuropsychology, identifying which region is damaged helps explain cognitive deficits, supporting clinical diagnosis and treatment.

STEP 6: CONCLUDE – SYNTHESISE

Instruction: Tie together both sides.

Overall, converging evidence from case studies, scanning, and surgical mapping strongly supports the theory of localisation of function. However, it must be understood as a general rule rather than a fixed blueprint. The brain shows individual differences, plasticity, and inter-regional cooperation. The best current view is that some functions are localised, but most involve interactive networks.

TASK 4: AO2 APPLICATION QUESTION – CLASS ACTIVITY

Lotta’s grandmother suffered a stroke to the left hemisphere, damaging Broca’s area and the motor cortex. Using your knowledge of the functions of Broca’s area and the motor cortex, describe the problems that Lotta’s grandmother is likely to experience. (4 marks) A02

Prompt:

• What difficulties might she experience based on what these areas control?

• What kind of evidence supports your answer?

• How would four marks be utilised?

SAMPLE AO2 ANSWER (4 MARKS):

Lotta’s grandmother will likely experience difficulty producing speech due to damage to Broca’s area, which controls language production. She may also struggle with voluntary movement on the right side of her body, as the motor cortex in the left hemisphere controls the opposite side. This prediction is supported by case studies such as Broca’s patient “Tan,” who had similar speech issues, and evidence from electrical stimulation and brain imaging, which consistently links these regions to their respective functions.

What a Good AO2 Answer Should Do (4 marks):

• Applies knowledge of brain areas to the specific case (Lotta’s grandmother)

• Shows understanding of contralateral control and function of Broca’s area.

• Supports with appropriate evidence (e.g. case studies, scans)

• It is concise, relevant, and avoids generic definitions — it applies theory to the scenario.

NOTES

KEYWORDS FOR: LOCALISATION OF BRAIN FUNCTION

AUDITORY CORTEX: Situated in the temporal lobe, it is responsible for processing sound information.

CORTEX: General term for the outer layer of the brain's regions in processing information.

CEREBRUM: The most significant part of the brain, including the cerebral cortex, is responsible for higher-order functions.

CEREBRAL CORTEX: The brain's outermost layer, responsible for higher cognitive functions.

COGNITIVE NEUROLOGIST: A specialist who studies how brain damage or neurological disorders affect cognitive functions like memory, language, and decision-making.

BRAIN LOBES: The four main lobes of the brain, each associated with specific functions:

FRONTAL LOBE: Responsible for reasoning, problem-solving, and motor control.

PARIETAL LOBE: Processes sensory information and spatial awareness.

OCCIPITAL LOBE: Primarily involved in visual processing.

TEMPORAL LOBE: Key for auditory processing and memory functions.

BROCA’S AREA: A region in the frontal lobe associated with speech production.

DISTRIBUTED PROCESSING: The concept that brain functions are not isolated but depend on networks of interconnected regions working together.

EQUIPOTENTIALITY THEORY: This theory suggests that while some essential functions may be localised, higher cognitive functions are more distributed across the brain.

HOMUNCULUS MAN: A visual representation of how different body parts are mapped onto the somatosensory and motor cortices according to the amount of control or sensory input they receive.

LOBES VS CORTICES: Lobes are the broader regions of the brain (e.g. frontal, temporal), while cortices are specialised areas within the lobes that handle specific tasks, such as the visual cortex for vision.

LOCALISATION OF FUNCTION: The theory that certain brain areas are specialised for specific functions, such as language or movement.

MOTOR CORTEX: Controls voluntary movements and is located in the frontal lobe.

NEUROIMAGING: Techniques such as fMRI and PET scans allow scientists to visualise brain activity and better understand the distribution of functions across different brain regions.

PHANTOM LIMB: The phenomenon where individuals who have had a limb amputated continue to feel sensations, including pain, in the missing limb, due to the brain’s sensory map.

PHRENOLOGY: A now-debunked theory that claimed the shape of the skull could determine personality traits and cognitive abilities by mapping bumps on the head.

POST-MORTEM: The examination of a body after death to determine the cause of death or study specific conditions, often used in brain research to examine the effects of brain damage on function.

PREFRONTAL CORTEX: The region at the front of the frontal lobe, associated with decision-making, personality, and social behaviour.

SOMATOSENSORY CORTEX: Found in the parietal lobe, it processes sensory inputs from the body, such as touch, pressure, and pain.

TOPOGRAPHICAL MAPPING: The brain organises the body's sensory and motor functions in a map-like representation, as seen in the motor and somatosensory cortices.

VISUAL CORTEX: Located in the occipital lobe, it processes visual information like shape, colour, and motion.

WERNICKE’S AREA: A region in the temporal lobe responsible for language comprehension.

TYPICAL RESEARCH METHODS USED IN LOCALISATION OF FUNCTION

• Cognitive Neuropsychology – studying damaged human brains through case studies. Post-mortems (e.g., Broca’s “Tan”) and later neuroimaging (fMRI, PET) were used. Especially important for speech areas where animal comparisons are not valid.

• Cognitive Neuroscience uses neuroimaging (fMRI, PET) to study healthy brains and validate earlier findings; it shows real-time activation (e.g., Dronkers, Fedorenko). Distributed networks and real-time activation are also relevant for testing modularity vs. integration.

• Lesion/ablation studies are mainly animal research to determine visual, motor, and sensory function (e.g., Hubel and Wiesel); they allow causal inferences but lack generalisability.

• Electrical stimulation/blockers in surgery – Sometimes used during live brain surgery in conscious humans, for example, when tumours are near Broca’s area. Also used experimentally on animals  (e.g. Penfield) to map motor and sensory cortices and localise other regions, e.g., the visual cortex.

AO2 & AO3 MULTIPLE CHOICE ANSWERS– LOCALISATION OF FUNCTION

1) C

2. C

3. A

4. C

5. B

6. B

7. A

8. B