Brain Damage & Behavior

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Localized Brain DamageThe Phineas Gage Case:

In the 1800s, a rod was shot through his head.

The doctor was amazed that he survived the

accident. While talking to the doctor, part of his

brain fell out.

When he recovered, people said Phineas didn’t act like himself anymore. His behavior

and personality had changed.

Localized Brain DamagePhineas is an early case study for

localized brain damage: damage that affects only a certain area of the brain.

Localized damage is commonly associated with an injury in which the head strikes or is struck by an object.

The opposite of localized brain damage is diffuse brain damage: damage that covers a widespread area in the brain (this is less common). Diffuse brain

damage is usually due to the death of brain tissue due to disease.

Brain Structure• The “Old Brain” (or “Reptilian Brain”) is the part of the

brain that controls eating, breathing, and sleeping. It is common to all vertebrates. The evolution of the “old brain” dates back

500 million years. • “The Midbrain” controls vision, hearing, motor control,

alertness, and temperature regulation.

Brain StructureThe “New Brain” is the cerebral

cortex: the outer layer of nerve tissue in our brains. It controls memory, attention, perceptual awareness,

thought, language, and consciousness. The cerebral cortex is the part of the brain that allows us to reason and that

gives us personality..

Brain Structure

Lobes of the Cerebral CortexFrontal Lobe: The function of the frontal lobe involves theability to recognize future consequences, the choice between good and bad actions, the differentiation between bad/good/better/best, the suppression of socially unacceptable behavior, and the ability to determine similarities and differences. It also helps us retain long term memories.

Localized Brain DamageDamage to the frontal lobe:

Generally, damage to the frontal lobe causes loss of the ability to solve problems and to plan and initiate actions, such as answering a complex

question. The frontal lobe also helps govern personality, impulsivity, and our ability to tell good from bad. If damaged, a person may find he

cannot control his anger or aggression. He may also make inappropriate comments to friends or strangers not realizing they

are inappropriate.

When did he become so rude

and socially inappropriate?

Damage to the middle back part of the left frontal lobe (Broca’s area)

causes people to have difficulty expressing themselves in words. They understand what people are saying and think clearly, but cannot make speech leave their mouths. They know what they want to say, but can’t make the words come out.

Video 1: Broca’s Aphasia

Wernicke's area is located where the temporal lobe and frontal lobe

meet. Like Broca’s area, it is involved in speech production. If someone

has damage in this area, they understand what people are saying and think clearly, but they speak rapidly in gibberish, not knowing that they are producing incorrect

words.

Video 2: Wernicke's Aphasia

Lobes of the Cerebral CortexParietal Lobe: It allows us to recognize objects by touch alone, manipulate objects with our hands, and understand how objects are positioned in space around us (spatial understanding). It also allows us to understand and manipulate numbers.

Localized Brain DamageDamage to the parietal lobe:

Affected people have difficulty identifying a sensation's location (where pain is coming from) and type (they can’t tell if they are

feeling something hot or cold). People may have difficulty recognizing objects by touch. They may not be able to tell right from left,

and have problems with calculations and writing. They may have problems sensing where parts of their body are. If the right parietal lobe is damaged, people may be

unable to do simple tasks, such as combing their hair or dressing. They have trouble

understanding space, and as a result may get lost in their own neighborhood.

Lobes of the Cerebral Cortex

Temporal Lobe: Involved in smell, sound, vision, and memory. Allows us to form, store, and retrieve long-term memories. It includes the auditory association area, which allows us to process sounds and comprehend speech. This lobe gives us the ability to recognize and name people and objects.

Localized Brain DamageDamage to the temporal lobe:

Part of the left temporal lobe controls language comprehension. If that part is damaged, memory for

words can be drastically impaired. If certain areas of the right temporal

lobe are damaged, memory for sounds and music may be impaired. As a result, people may have trouble singing. Sometimes damage can cause

personality changes such as humorlessness, extreme religiosity,

and obsessiveness. Those affected may not be able to control

their feelings or to think clearly. HUMORLESS

Lobes of the Cerebral CortexOccipital Lobe: The primaryvisual processing center of the brain, the occipital lobe allows you to process and understand what you are seeing. This lobe allows us to differentiate between different colors and perceive motion.

Localized Brain DamageDamage to the occipital lobe:

The occipital lobe contains the main center for processing visual information. If the

occipital lobe on both sides of the brain is damaged, people cannot see, even though the eyes themselves are functioning normally. If

the front part is damaged, people have difficulty recognizing familiar objects and faces

and accurately interpreting what they see.

http://www.merckmanuals.com

“Face Blindness”

Video

Types of Brain DamagePhysical Trauma

Blunt force to the head. Example causes: Concussion. The tearing of brain structures from shaking or strong rotation of the head. The impact of a bullet, knife or other sharp object, etc. (Can be localized or diffuse).

Anoxic/Hypoxic Brain

Injury

This is when the brain does not receive any oxygen (anoxic) or enough oxygen (hypoxic), causing brain cells to die. Example causes: suffocation

or near-drowing experiences. This type of damage is diffuse (not localized).

StrokeLike the above, stroke occurs when there is a lack of blood-supply to the brain, preventing brain cells from getting oxygen. Clotted blood vessels

or internal bleeding in the brain may be the cause. Stroke damage is localized (not diffuse).

Brain Tumor Tumors in the brain can put pressure on certain areas, causing brain damage similar to the kinds that results from a traumatic brain injury.

Disease Infections in the brain cause inflammation that puts pressure in localized areas. Diseases with unknown causes cause brain cells to die.

StrokeA stroke is the loss of brain function due to a lack of

blood-supply to the brain. It is caused by clotted (blocked) blood vessels, internal bleeding in the brain,

or other complications that arise as side-effects of certain diseases. After a stroke, the affected area of the brain

cannot function normally. Stroke creates localized damage.

1 in 6 people worldwide will have a stroke in their lifetime

TumorTumors in the brain can put pressure on certain areas,

causing brain damage similar to the kinds that results from a traumatic brain injury. Language and communication, emotion

and personality, learning and memory, attention and concentration, and intellectual abilities can all be affected in

negative ways. A tumor is an abnormal tissue growth.

DiseasesList of diseases that cause brain damage:

1. Meningitis: inflammation of the lining around the brain or spinal cord, usually due to infection.

2. Encephalitis: inflammation of the brain tissue, usually due to a viral infection.

3. Epilepsy: recurring seizures caused by abnormal and excessive electrical activity in the brain.

4. Brain abscess: an infected area in the brain, usually caused by bacteria.

5. Alzheimer's disease or dementia: memory loss due to death of brain cells.

6. Multiple Sclerosis: destruction of nerve fibers that causes communication problems between your brain and the rest of your body.

7. Parkinson's disease: motor control loss due to death of brain cells.

Normal Brain Alzheimer's Brain

Slow deterioration of brain cells over time.

Diseases

Bonus! Ms. Georgi demonstrates what can

happen when inflammation in your

brain presses down on your facial nerve…

Video

Research Challenge:Choose one of the following questions, and conduct research online to seek an answer. Be prepared to

describe your findings to the class.

Does watching too much TV damage your brain?

Does extreme stress damage your brain?

Does too much sugar cause brain damage?

Does a high fever cause brain damage?

Does radiation from cell phones cause brain damage?