Brain and Neuropsychology

What you'll learn

This revision guide covers the biological basis of behaviour through brain structure and function. You'll learn how neurons transmit information, how different brain regions control specific functions, and how psychologists investigate the brain using scanning technology. These topics form the foundation of understanding how our biology influences behaviour and mental processes.

Key terms and definitions

Neuron — A specialised nerve cell that transmits electrical impulses throughout the nervous system; the basic building block of the nervous system.

Synapse — The microscopic gap between two neurons where neurotransmitters are released to pass signals from one neuron to another.

Neurotransmitter — A chemical messenger (such as serotonin or dopamine) released from one neuron that crosses the synapse to transmit signals to the next neuron.

Localisation of function — The principle that specific areas of the brain are responsible for particular functions and behaviours.

fMRI (functional Magnetic Resonance Imaging) — A brain scanning technique that measures blood flow to detect which areas of the brain are active during different tasks.

CT scan (Computerised Tomography) — A brain scanning technique that uses X-rays to create detailed images of brain structure, useful for detecting physical damage.

Cerebral cortex — The outer layer of the brain responsible for higher-level thinking, consciousness, and complex behaviours.

Hemispheric lateralisation — The tendency for the left and right hemispheres of the brain to specialise in different functions.

Core concepts

Structure and function of neurons

Neurons are specialised cells designed to transmit electrical and chemical signals throughout the body. Understanding their structure helps explain how information travels through the nervous system.

Key components of a neuron:

• Dendrites — Branch-like structures that receive signals from other neurons
• Cell body (soma) — Contains the nucleus and controls the neuron's metabolic functions
• Axon — A long fibre that carries electrical impulses away from the cell body
• Myelin sheath — A fatty insulating layer covering the axon that speeds up signal transmission
• Terminal buttons — End points of the axon where neurotransmitters are stored and released

How neurons communicate:

1. An electrical impulse (action potential) travels down the axon
2. When the impulse reaches the terminal buttons, neurotransmitters are released
3. Neurotransmitters cross the synapse
4. They bind to receptor sites on the dendrites of the next neuron
5. This triggers a new electrical impulse in the receiving neuron

Types of neurons:

• Sensory neurons — Carry messages from sensory receptors to the central nervous system
• Motor neurons — Carry messages from the central nervous system to muscles and glands
• Relay neurons — Connect sensory and motor neurons, found in the brain and spinal cord

The structure of the brain

The brain consists of several distinct regions, each responsible for different functions. WJEC GCSE requires you to know the main areas and their primary roles.

The cerebrum:

The largest part of the brain, divided into two hemispheres (left and right). The outer layer is the cerebral cortex, responsible for conscious thought, memory, language and perception.

The cerebrum is divided into four lobes:

• Frontal lobe — Decision-making, planning, problem-solving, personality, and motor control (includes the motor cortex)
• Parietal lobe — Processing sensory information from the body, spatial awareness (includes the somatosensory cortex)
• Temporal lobe — Processing auditory information, language comprehension (Wernicke's area), and memory
• Occipital lobe — Processing visual information (visual cortex)

The cerebellum:

Located at the back of the brain beneath the cerebrum. Coordinates muscle movement, balance, and posture. Damage to the cerebellum results in jerky, uncoordinated movements.

The brain stem:

Connects the brain to the spinal cord. Controls automatic life-sustaining functions including:

• Heart rate
• Breathing
• Swallowing
• Blood pressure

Localisation of brain function

Different brain regions specialise in particular functions. This concept is crucial for understanding case studies and brain damage research.

Key specialised areas:

Motor cortex — Located in the frontal lobe. Controls voluntary muscle movements. The left motor cortex controls the right side of the body and vice versa (contralateral control).

Somatosensory cortex — Located in the parietal lobe. Processes sensory information from the skin (touch, temperature, pain). Also shows contralateral representation.

Visual cortex — Located in the occipital lobe. Processes visual information from the eyes. Damage causes partial or complete blindness.

Auditory cortex — Located in the temporal lobe. Processes sound information from the ears.

Broca's area — Located in the left frontal lobe. Responsible for speech production. Damage causes Broca's aphasia: difficulty producing fluent speech whilst comprehension remains largely intact.

Wernicke's area — Located in the left temporal lobe. Responsible for language comprehension. Damage causes Wernicke's aphasia: fluent but meaningless speech with poor comprehension.

Evidence for localisation:

• Brain damage case studies — Patients like Phineas Gage demonstrated that frontal lobe damage affects personality and decision-making
• Brain scanning — fMRI studies show specific areas activate during particular tasks
• Surgical lesion studies — Deliberate damage to specific areas in animals shows functional changes

Limitations of strict localisation:

• Many functions involve multiple brain areas working together (distributed processing)
• The brain shows plasticity — other areas can sometimes compensate for damaged regions
• Individual differences exist in exact localisation patterns

Hemispheric lateralisation

The left and right hemispheres of the brain have some specialised functions, though they work together for most tasks.

Left hemisphere typically controls:

• Language production and comprehension (in 95% of right-handed people)
• Logical reasoning
• Mathematical calculations
• Analytical thinking
• Right side of the body

Right hemisphere typically controls:

• Spatial awareness and visual-spatial tasks
• Face recognition
• Emotion recognition
• Creativity and artistic ability
• Left side of the body

Communication between hemispheres:

The corpus callosum is a thick bundle of nerve fibres connecting the two hemispheres, allowing them to share information and coordinate activity.

Split-brain research:

Studies of patients who had their corpus callosum severed (to treat severe epilepsy) revealed hemispheric specialisation. For example, when an object was shown only to the left visual field (processed by the right hemisphere), patients could not name it because language is in the left hemisphere.

Brain scanning techniques

Psychologists use various scanning methods to study brain structure and function. You need to know the uses, strengths and limitations of each technique.

CT (Computerised Tomography) scan:

How it works: Multiple X-ray images are taken from different angles and combined by computer to create detailed cross-sectional images of the brain.

Uses:

• Detecting structural abnormalities (tumours, bleeding, blood clots)
• Identifying brain damage after stroke or injury
• Quick to perform, useful in emergencies

Strengths:

• Provides clear images of brain structure
• Relatively inexpensive compared to other scanning methods
• Widely available in hospitals
• Useful for detecting physical damage

Limitations:

• Uses radiation (X-rays) which carries small health risks
• Only shows structure, not function or activity
• Lower resolution than MRI scans
• Cannot show how the brain works during different tasks

fMRI (functional Magnetic Resonance Imaging):

How it works: Uses powerful magnetic fields to detect changes in blood oxygenation. Active brain areas require more oxygen, so increased blood flow indicates neural activity.

Uses:

• Identifying which brain areas are active during specific tasks
• Pre-surgical planning to avoid damaging critical areas
• Research into brain function and psychological processes
• Studying effects of brain injury or disease

Strengths:

• Shows brain activity in real-time (functional information)
• Non-invasive and does not use radiation
• Excellent spatial resolution (pinpoints active areas accurately)
• Can be used repeatedly on the same person safely

Limitations:

• Expensive to purchase and run
• Requires person to remain very still, limiting task types
• Claustrophobic for some participants
• Only shows correlation between brain activity and behaviour, not causation
• Poor temporal resolution (several seconds delay)
• Very noisy, which can be stressful

Neuroplasticity

The brain's ability to change and reorganise itself throughout life is called neuroplasticity or brain plasticity.

Types of plasticity:

Developmental plasticity — The brain's rapid growth and reorganisation during childhood. Neural connections are strengthened through use and pruned if not used.

Adaptive plasticity — The brain's ability to compensate for injury or adapt to new experiences. Undamaged brain areas can sometimes take over functions from damaged regions.

Evidence for plasticity:

• Taxi driver study (Maguire et al.) — London taxi drivers showed increased grey matter in the hippocampus (involved in spatial memory) compared to controls. The longer they'd been driving, the greater the difference.
• Stroke recovery — Some stroke patients regain lost functions as other brain areas compensate, though recovery is often incomplete
• Phantom limb — After amputation, the somatosensory cortex area for the missing limb may respond to stimulation of nearby body parts

Limitations:

• Plasticity decreases with age (children recover better from brain injury)
• Not all functions can be relocated successfully
• Recovery depends on injury location, extent and individual factors

Worked examples

Example 1: Short-answer question (3 marks)

Question: Outline one difference between a CT scan and an fMRI scan.

Mark scheme answer: A CT scan shows the structure of the brain (1 mark) whereas an fMRI scan shows brain activity/function (1 mark). CT scans use X-rays whilst fMRI uses magnetic fields to detect blood flow changes (1 mark).

Alternative acceptable answer: fMRI scans can show which areas of the brain are active during different tasks (1 mark) but CT scans only show static images of brain structure (1 mark). This means fMRI is better for studying how the brain works during behaviour whilst CT is better for detecting physical damage (1 mark).

Example 2: Application question (4 marks)

Question: James suffered damage to his frontal lobe in a car accident. Explain two problems James might experience as a result of this damage.

Mark scheme answer: James might have difficulty with planning and decision-making (1 mark) because the frontal lobe is responsible for executive functions and organising behaviour (1 mark). He might also experience personality changes such as becoming more impulsive or disinhibited (1 mark) as the frontal lobe controls aspects of personality and self-regulation (1 mark).

Example 3: Extended response question (6 marks)

Question: Describe how information is transmitted from one neuron to another.

Mark scheme answer (indicative content):

• An electrical impulse/action potential travels down the axon of the first neuron (1 mark)
• When the impulse reaches the terminal buttons/end of the axon, it triggers the release of neurotransmitters (1 mark)
• Neurotransmitters are chemical messengers stored in vesicles (1 mark)
• The neurotransmitters are released into the synapse/synaptic gap between the neurons (1 mark)
• They diffuse across the synapse and bind to receptor sites on the dendrites of the receiving neuron (1 mark)
• This binding triggers a new electrical impulse in the second neuron, continuing the signal (1 mark)

Examiner note: Full marks require clear description of the process in sequence. Technical terminology must be used accurately. Diagrams can support but not replace written explanation.

Common mistakes and how to avoid them

• Confusing structure and function — Remember CT scans show structure (what the brain looks like) whilst fMRI shows function (what the brain is doing). Don't mix these up when describing scanning techniques.

• Reversing contralateral control — The left hemisphere controls the right side of the body, not the left. Always double-check this in exam answers about motor cortex or brain damage.

• Muddling Broca's and Wernicke's areas — Broca's is for production (speaking), Wernicke's is for comprehension (understanding). Memory tip: "Broca's for blabbing, Wernicke's for working out what others say."

• Oversimplifying lateralisation — Avoid saying "the left brain is logical, the right brain is creative" as if they work independently. The hemispheres work together for most tasks and lateralisation varies between individuals.

• Vague descriptions of neuron communication — Use precise terminology: synapse (not "gap"), neurotransmitter (not "chemical"), dendrites and axon (not just "the end bits"). Examiners award marks for technical accuracy.

• Confusing neurons with neurotransmitters — Neurons are cells; neurotransmitters are chemicals. They're related but distinct concepts that shouldn't be used interchangeably.

Exam technique for "Brain and Neuropsychology"

• Command words matter — "Outline" requires brief description (2-3 sentences), "Describe" needs more detail, "Explain" requires reasons/mechanisms. For "Evaluate," always provide both strengths and limitations with evidence.

• Use the mark allocation — For a 4-mark question, aim for 4 distinct points. If it says "Explain two reasons" (4 marks), that's 1 mark for identifying each reason plus 1 mark for elaborating each = 4 marks total.

• Name specific brain areas — Don't write "the part of the brain that controls movement." Use "motor cortex" or "frontal lobe." Precision earns marks and demonstrates knowledge.

• Link scanning techniques to real applications — When evaluating brain scans, mention practical uses (diagnosing tumours, planning surgery, research) not just abstract strengths. This shows applied understanding.

Quick revision summary

Neurons transmit information electrically along axons and chemically across synapses using neurotransmitters. The brain shows localisation of function: specific regions control particular behaviours and processes. The motor cortex controls movement, Broca's area controls speech production, and Wernicke's area controls language comprehension. The left hemisphere typically handles language whilst the right processes spatial information. CT scans reveal brain structure using X-rays; fMRI scans show brain activity through blood flow changes. Neuroplasticity allows the brain to reorganise and adapt throughout life, though this ability decreases with age.