Structure of the Brain

The human brain is the most complex organ in the body, containing approximately 86 billion neurons. Understanding the basic structure of the brain is essential for GCSE Psychology, as it underpins topics such as memory, perception, language, and psychological disorders. The brain is divided into distinct regions, each responsible for different functions.

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The Cerebral Cortex

The cerebral cortex is the outer layer of the brain, often called grey matter due to its colour. It is the largest part of the human brain and is responsible for higher cognitive functions such as thinking, reasoning, language, memory, and voluntary movement.

The cerebral cortex is divided into two hemispheres (left and right), connected by a thick band of nerve fibres called the corpus callosum. Each hemisphere is divided into four lobes:

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The Four Lobes of the Brain

1. Frontal Lobe

The frontal lobe is located at the front of the brain. It is the largest lobe and is responsible for:

Function	Description
Voluntary movement	The motor cortex (in the frontal lobe) controls conscious movements of the body
Higher cognitive functions	Reasoning, planning, problem-solving, decision-making
Personality and behaviour	Involved in personality expression and social behaviour
Speech production	Broca's area (in the left frontal lobe) is responsible for producing speech

Key case study: Phineas Gage (1848) — a railway worker who survived a metal rod being driven through his frontal lobe. His personality changed dramatically — he became impulsive, rude, and unable to plan ahead. This case provided early evidence that the frontal lobe is involved in personality and decision-making.

2. Temporal Lobe

The temporal lobe is located at the sides of the brain (near the temples). It is responsible for:

Function	Description
Auditory processing	Processing sounds and interpreting speech
Memory	The hippocampus (located within the temporal lobe) is crucial for forming new long-term memories
Language comprehension	Wernicke's area (in the left temporal lobe) is responsible for understanding language

3. Parietal Lobe

The parietal lobe is located at the top of the brain, behind the frontal lobe. It is responsible for:

Function	Description
Somatosensory processing	Processing sensory information from the body (touch, temperature, pain, pressure)
Spatial awareness	Understanding the position of the body in space and the location of objects
Numerical processing	Involved in mathematical thinking and calculations

4. Occipital Lobe

The occipital lobe is located at the back of the brain. Its primary function is:

Function	Description
Visual processing	Contains the visual cortex, which processes information from the eyes — interpreting colour, shape, depth, and movement

Damage to the occipital lobe can result in visual impairments or blindness, even if the eyes themselves are functioning normally.

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The Cerebellum

The cerebellum (meaning "little brain") is located at the back and base of the brain, beneath the occipital lobe. It is responsible for:

• Coordination of voluntary movements
• Balance and posture
• Motor learning — learning skilled movements (e.g. riding a bicycle, playing a musical instrument)
• Fine-tuning and smoothing of movements

Damage to the cerebellum results in ataxia — uncoordinated, clumsy movements, difficulty with balance, and problems with fine motor skills.

The cerebellum is also associated with procedural memory — the memory for how to do things (e.g. tying shoelaces, playing piano). This explains why procedural memories are often preserved even when other types of memory are damaged.

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Summary Table

Brain Region	Location	Key Functions
Frontal lobe	Front	Movement, thinking, planning, personality, speech production (Broca's area)
Temporal lobe	Sides	Hearing, memory, language comprehension (Wernicke's area)
Parietal lobe	Top	Touch, spatial awareness, numerical processing
Occipital lobe	Back	Vision (visual cortex)
Cerebellum	Back/base	Coordination, balance, motor learning, procedural memory

Exam Tip: You must be able to identify and describe the function of each lobe and the cerebellum. A common question format is: "Describe the role of [brain region]." Always state both the location and the function.

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Key Points

• The brain has four lobes: frontal (movement, thinking, personality), temporal (hearing, memory, language comprehension), parietal (touch, spatial awareness), occipital (vision).
• The cerebellum coordinates movement, balance, and procedural memory.
• Brain regions have specialised functions — damage to a specific area impairs specific abilities.
• Key case: Phineas Gage demonstrated the frontal lobe's role in personality.