Unit 1 Psychology
Area of Study 1: How does the brain function?
Key knowledge: Dot point 3
“The basic structure and function of the hindbrain (cerebellum, medulla), midbrain (reticular
formation) and forebrain (hypothalamus, thalamus and cerebrum).”
The Hindbrain
The hindbrain is a collection of lower level brain structures that include the cerebellum, medulla and
pons. These control or influence various motor functions and vital, automatic responses such as
breathing and heart rate, as well as seep and arousal (alertness).
The two main structures of the hindbrain are the cerebellum and medulla.
Cerebellum: a cauliflower-shaped structure, located at the base of the brain, about the size of a
tennis ball in adult brains. The cerebellum coordinates fine muscle movements and regulates
posture and balance.
It ensures movements are smooth and precise. It is involved in activities requiring a rapid and skilled
sequence of movements and most active in learning new skills and voluntary, purposeful
movements.
If the cerebellum is damaged, muscle movement may be impaired and balance is affected. Speech
can also be affected, as the cerebellum involves controlling the muscle movements in speech.
Medulla: controls vital bodily functions such as swallowing, breathing, heart rate, blood pressure,
vomiting, salivating, coughing and sneezing, all of which occur automatically and are essential for
survival.
The Midbrain
The midbrain is a collection of structures involved with movement, processing of visual, auditory and
tactile sensory information, sleep and arousal.
Information from the eyes and ears are used to help orient movements.
The major structure of the midbrain is the reticular formation.
Reticular formation: screens incoming information so as not to overload the brain, alerts higher
brain centres to important information, helps maintain consciousness, and regulates arousal and
muscle tone (tension).
The reticular formation extends into different parts of the brain and spinal cord. It responds to
feedback from brain areas to influence whether we are awake, drowsy, asleep or somewhere in
between. More active = awake, less active = asleep.
The Forebrain
The Forebrain is the upper area of the brain that includes the hypothalamus, thalamus and
cerebrum. The forebrain coordinates and controls complex cognitive functions such as thinking,
learning, memory and perception.
Hypothalamus: maintains the body’s internal environment and takes part in numerous behaviours.
Its main functions are to regulate the release of hormones and influence behaviours associated with
basic biological needs such as hunger, thirst and sleep.
The hypothalamus is located below the thalamus and is about the size of a pea or sultana.
The hypothalamus connects the nervous system and endocrine system. It directs the Pituitary Gland
to release hormones into the body when needed.
For example: the stress hormone cortisol is released when a person experiences stress over a long
period (for example Year 12). Once the stress is dealt with, cortisol is no longer needed and the
hypothalamus stops its production.
Damage to the hypothalamus can cause problems regulating functions such as hunger and the sleepwake cycle.
Thalamus: filters information from almost all the receptor sites (except smell) then passes it on to
the relevant brain area for processing.
If you stick your fingers in your ears until they touch – that’s where the thalamus is.
3cm in length, looks like two footballs (ovids), one per hemisphere.
Thalamus is a relay station. It filters all sensory information, except smell, and transmits it to the
relevant area of the cerebral cortex.
Information from the Reticular Formation goes to the Thalamus to assist in level of alertness and
wakefulness.
Injury to Thalamus
= loss of senses. EG blindness, deafness, except smell.
= loss of arousal – lethargy through to coma.
Thalamus further filters information to direct our attention.
Thalamus closes off pathways of incoming sensations during sleep to allow the brain to rest.
Cerebrum: consists of the outer layer of the forebrain, known as the cerebral cortex. It is divided
into two hemispheres which are connected by the corpus callosum (a bundle of nerve fibres). The
cerebrum is responsible for all higher mental functioning.