Chapter 4: Central nervous system

Brain structure and cognitive processes

VCE Psychology Units 3 & 4

Parts of the brain

The central nervous system is made up of many different components. The cerebral cortex is what we usually mean when we refer to the brain, but it is only one part.

This presentation will use structures and divisions to teach you about different brain functions.

There are different ways of approaching this.

Cerebellum

Midbrain

Spinal cord

Cerebral cortex

Source: Brand X

If we were to view the brain from the top, it can be divided into left and right hemispheres.

These are joined together by a band of nerve tissue called the corpus callosum.

Corpus callosum

Parts of the brain

Source: Getty

Lobes of the cerebral cortex

•frontal lobe•parietal lobe•occipital lobe•temporal lobe.

Each hemisphere can also be divided into four lobes:

The lobes contain areas of the cortex that specialise in particular functions.

Frontal lobe

The frontal lobe:

• includes the primary motor cortex which controls voluntary bodily movements

• performs complex mental functions

• is involved with attention, personality, control of emotions and expression of emotional behaviour

• also contains Broca’s area, in the left hemisphere, which plays a crucial role in speech production.

Parietal lobe

Parietal lobe:

• includes the primary sensory cortex, which receives and processes sensory information

• is also involved in attention and spatial reasoning

• liaises with other lobes to allow us to sense the position of our body in space.

• A huge part of the primary sensory cortex is devoted to sensations of the mouth and hands.

Temporal and occipital lobes

Temporal lobe:

• contains the primary auditory cortex, which receives and processes sounds from both ears

• is also involved in memory, visual perception, object identification and emotional responses to sensory information and memories

• also contains Wernicke’s area, in the left hemisphere, which is crucial in speech comprehension.

Occipital lobe:

• contains the primary visual cortex

• is largely engaged in the sense of vision, but also interacts with other lobes to integrate visual information with other information, like memory, language and sounds.

Lobes of the cerebral cortexMoving clockwise from the top, label each part of the brain.

12

3

4

5

67

8

9

10

Hemisphere specialisation

While both hemispheres are involved in almost all brain functions, hemispheres can exert greater control in clearly distinguishable functions.

Which do you think is your dominant hemisphere?

How could you test someone’s hemisphere specialisation?

RAS and thalamus

The reticular activating system (RAS) is a network of neurons that extends from the reticular formation to parts of the brain and spinal cord. It is largely responsible for our level of alertness.

The thalamus filters information from the senses and transmits that information to the cerebral cortex. It prioritises and filters this sensory information. Only smell has a direct route to the cerebral cortex.

The spinal cord

The spinal cord is made up of the column of nerve fibres from the base of the brain to the lower back. It receives sensory information from the body to transmit to the brain, and vice versa. It integrates the central nervous system and the peripheral nervous system.

Quick quiz• Question 1: What are the two cerebral hemispheres connected by? • Answer: The corpus callosum. • Question 2: Which parts of the body have the highest proportional

representation on the primary sensory cortex?• Answer: The hands and the mouth.• Question 3: Where is Broca’s area located?• Answer: On the left frontal lobe. • Question 4: State three cognitive functions of the left hemisphere.• Answer: Language, analysis, logical reasoning, verbal skills. • Question 5: Which lobe contains the primary visual cortex?• Answer: The occipital lobe. • Question 6: What is the role of the temporal lobe?• Answer: It is largely involved in auditory processing, but it is also involved in

memory, visual perception and emotional responses.• Question 7: Which sense bypasses the thalamus and goes directly to the

cerebral cortex?• Answer: Smell. • Question 8: What two systems does the spinal cord integrate?• Answer: Central and peripheral nervous systems.