The Brain

Module 08

I. Lower-Level Structures

Brainstem, Thalamus, and Cerebellum

A. Brainstem

• The oldest part of the brain

• Responsible for automatic survival functions

1. Medulla

• Controls heartbeat and breathing

• Damage to this area can lead to death.

2. Reticular Formation

• Controls alertness

• Damage to this area can cause a coma.

B. Thalamus

• The brain’s sensory switchboard -- directs messages from sensory organs to the correct area of the brain

C. Cerebellum

• Helps coordinate voluntary movements and balance

• Damage to this area can cause loss of fine motor skills – Small yet controlled, skilled movements;

such as writing or playing guitar

II. Limbic System

Helps regulate memory, aggression, fear, hunger, and

thirst

Includes Hypothalamus, Hippocampus, and Amygdala

A. Hypothalamus

• Regulates eating, drinking, body temperature, libido, and the “fight or flight” reaction

B. Hippocampus

• Part of the limbic system that helps us form new memories

• Looks like a seahorse

– Hippo is Greek for “horse.”

“If you saw a hippo on campus, you’d never forget it!”

C. Amygdala

• Controls emotional responses such as fear and anger

• Damage to this area could result in violent, aggressive behavior

III. Cerebral Cortex

Module 8: The Brain

•The body’s ultimate control and information processing center

A. Corpus Callosum

• Connects the two brain hemispheres

• Is sometimes cut to prevent seizures

B. The Four Lobes

Frontal, Parietal, Occipital, and Temporal

1. Frontal Lobes

• Located just behind the forehead

• Involved in personality, making plans and judgments

2. Parietal Lobes

• Involved in making associations

• Located behind the frontal lobes

3. Occipital Lobes

• The primary visual processing area

• Located in the back of the head

• Damage to this area could result in loss of vision

4. Temporal Lobes

• Auditory (sound) information is first processed here

• Located above the ears

Cerebral Cortex

Cerebral Cortex

Cerebral Cortex

Cerebral Cortex

IV. Hemispheric Differences

Module 8: The Brain

A. Left Hemisphere

• Spoken language is one of the clearest differences between the two hemispheres.

• For most people, language functions are in the left hemisphere.

1. Broca’s Area

• Located in the frontal lobe, usually in the left hemisphere

• Responsible for the muscle movements of speech

• Damage to this area causes problems in expressing thoughts in spoken language

PET Scan of Broca’s Area

Broca’s Area

This is the brain of “Tal” from whom Broca discovered the area for speech. Note the damage to Broca’s Area.

2. Wernicke’s Area

• Located in the temporal lobe (usually on the left side)

• Gives us the ability to understand what is said to us

PET Scan of Wernicke’s Area

B. Right Hemisphere

• Spatial skills - being able to perceive or organize things in a given space, judge distance, etc.

• Relationships and emotions

Right Brain: emotion, relationships, musicLeft

Brain

: language, m

ath, r

easonin

g

C. Plasticity

• The ability of the brain tissue to take on new functions

• Greatest in childhood

• Important if parts of the brain are damaged or destroyed

V. Imaging Techniques

1. CAT Scan: X-rays taken from different angles of the brain

2. MRI: computer generated images of soft tissue in the brain

3. EEG: electrodes on the scalp measure waves of electrical activity in the brain

4. PET: a visual display of brain activity based on glucose (blood sugar)

The End

Any questions?