The Brain
A Brief Lesson on the Parts of the
Brain and their Functions
Brain Stats
• “the best organized, most functional three
pounds of matter in the known universe.”
• 100 million interconnected neurons
• has the consistency of refrigerated butter
• weighs 2% of our body weight
• uses about 20% of our body’s energy
• arterial blood from the heart goes to the
brain first and the brain takes what it needs
to survive.
• http://www.youtube.com/watch?v=Li5nMsXg1Lk&feature=related
Basic Parts of the Brain
• Subcortical area (lower brain)
– maintains the basic body functions
• Cerebral Cortex (upper brain)
– The outer layer of the brain that contains the
four major lobes and the two hemispheres
– 77% of our brain
– Roughly the size of six 12”x18” sheets of
construction paper
Frontal Lobe
Sensory Strip
(Orange)
Motor Strip
Parietal Lobe
(Blue)
(Pink)
Occipital Lobe
(Red)
Temporal Lobe
(Green)
Brain Stem
The Lobes of the Human Brain
• Frontal Lobe: Associates ideas, forms and
plans activities, social control.
• Parietal Lobe: Area that contains the Sensory Strip.
Interprets physical sensation.
• Occipital Lobe: Area that makes sense out of
what we see.
• Temporal Lobe: Area responsible for hearing
and some speech functions.
Also, memory (hippocampus)
Motor Strip and Sensory Strip
• Motor Strip:
Band running down the side of the
Frontal Lobe that controls all
bodily movements.
• Sensory Strip
Band running down the side of the
Parietal Lobe that registers and
provides all sensation.
The Motor Strip
Three Brains in One…
Three Brains
Each of our brains can be divided into three parts:
• Forebrain: Responsible for reasoning and logic
• Midbrain: Relay Station between the Forebrain
and the Hindbrain
• Hindbrain: Basic life support functions and
muscle coordination
Cerebral Cortex
Thalamus
Hypothalamus
Amygdala
Hippocampus
Reticular
activating
system
Cerebellum
Another Image of the Brain
Other Parts of the Brain
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Cerebral Cortex – Upper Brain
Limbic System
Amygdala – Located in the Temporal Lobe
Hippocampus – Located in the Temporal Lobe
Thalamus
Hypothalamus
Pons
Medulla or Brain Stem
Cerebellum
Reticular Activating System
Forebrain
Cerebral Cortex
Limbic System
Amygdala
Hippocampus
Thalamus
Hypothalamus
Cerebral Cortex
• The “outer shell” or “upper brain.”
• 1/8th inch thick.
• Controls all mental processes and thought
but will not keep the body running.
• Contains over 100 billion neuron cells (2/3
of all the brains nerve cells).
• Neurons connect to Axons which
communicate with other parts of the brain.
• Estimated that the number of connections
between these nerves is greater than the
number of particles in the universe.
Limbic System
• A group of brain
structures involved with:
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Memory and motivation
emotion
Body function
Smell
• Contains the Amygdala
and the Hippocampus
Amygdala
The amygdala is located within the temporal
lobe and controls social and sexual behavior
and other emotions like aggression & fear.
Adds positive and negative feelings to long
term memories for later use.
The Amygdala is the size and shape of an
almond
Hippocampus
The hippocampus is located within the
temporal lobe and is important for learning
long-term memory.
Thalamus
The Thalamus is the “relay station” of the nervous
system: it sends incoming and outgoing
messages between the brain and body.
It relays all sensory information except that of
smell
The Thalamus is a pair and they are the size of
golf balls
Hypothalamus
Regulates your basic needs, such as hunger
and thirst, and emotions such as pleasure,
fear, rage, and sexuality.
If a person’s rage center is stimulated that
person will go on a smashing spree
The Hypothalamus is only the size of a large
pea or a small cherry.
Midbrain: Reticular Activating
System
The alertness control center that regulates the
activity level of the body.
It controls stimuli that travel from the body to
the brain, regulating pain.
Also controls sleepiness that comes from
boredom.
Hindbrain
Pons
Cerebellum
Medulla
Pons
Named from the Latin word for ‘bridge’
Responsible for regulating sleep and relaying
information from the brainstem (medulla)
and the hindbrain
Cerebellum
The part of the brain that coordinates and
organizes bodily movements for balance
and accuracy.
It looks like a ball of yarn a little larger than a
golf ball.
Medulla (Brain Stem)
Responsible for breathing and heart rate
Connects the nerve pathways between the
brain and the body
Damage to the Frontal Lobe
Damage to the Frontal Lobe can cause:
• Loss of simple movement of various body parts
(Paralysis).
• Inability to plan a sequence of complex movements
needed to complete multi-stepped tasks, such as
making coffee (Sequencing).
• Loss of spontaneity in interacting with others.
• Loss of flexibility in thinking.
• Persistence of a single thought (Perseveration).
• Inability to focus on task (Attending).
• Mood changes and Changes in social behavior.
Phineas Gage
Explosive powders propelled a three and a half foot long iron rod into
Phineas Gage's face. It pierced his left cheek, traveled behind his eye, and
flew out the top of his skull. He didn't die. In fact, almost immediately after
the accident, Gage could talk and walk.
Before the accident, Gage had been a responsible, hard-working, fit and
popular man. After the accident, Gage became a nasty, vulgar, irresponsible
vagrant. His former employer, who regarded him as "the most efficient and
capable foreman in their employ previous to his injury," refused to rehire him
because he was so different.
Damage to the Parietal Lobe
Damage to the parietal lobe can cause:
• Inability to attend to more than one object at a time.
• Inability to name an object (Anomia).
• Inability to locate the words for writing (Agraphia).
• Problems with reading, drawing and math.
• Difficulty in distinguishing left from right.
• Lack of awareness of certain body parts and/or
surrounding space (Apraxia) that leads to difficulties
in self-care.
• Inability to focus visual attention.
• Difficulties with eye and hand coordination.
Damage to the Occipital Lobe
Damage to the Occipital Lobe can cause:
• Defects in vision
• Difficulty with locating objects in environment.
• Difficulty with identifying colors
• Production of hallucinations
• Visual illusions - inaccurately seeing objects.
• Word blindness - inability to recognize words.
• Difficulty in recognizing drawn objects.
• Inability to recognize the movement of an object
• Difficulties with reading and writing.
Damage to the Temporal Lobe
Damage to the Temporal Lobe can cause:
• Difficulty in recognizing faces (Prosopagnosia).
• Difficulty in understanding spoken words
• Disturbance with selective attention to what we see and
hear.
• Difficulty with identification of, and verbalization about
objects.
• Short-term memory loss.
• Interference with long-term memory
• Increased or decreased interest in sexual behavior.
• Inability to catagorize objects
• Right lobe damage can cause persistant talking.
• Increased aggressive behavior.
2 Brains in 1
Right and Left Hemisphericity
Brain Hemispheres
• The Human Brain is divided into two
hemispheres: Left and Right.
• The two hemispheres are connected by a thick
bundle of nerves called the Corpus Callosum.
• Each hemisphere is responsible for different kinds
of tasks, or kinds of thinking.
• Research shows that most people prefer one side
to the other and that this side is “dominant.”
Left Brain
The Left Hemisphere controls:
• Muscles on the right side of the body
• In most people the left side is dominant for
language skills.
• Left Brained thinking is considered to be:
Logical, Sequential, Rational, Analytical,
Objective, Looks at parts
• Damage to the Left side will effect the
Right side of the body.
Right Brain
The Right Hemisphere controls:
• Muscles in the Left side of the body
• Right Brained thinking is considered to be:
Random, Intuitive, Holistic, Synthesizing,
Subjective, Looks at wholes
• Damage to the Right side will effect the
Left side of the body.
Split Brain Experiments
• In the 1960s a popular “cure” for epilepsy
was to cut the Corpus Callosum, separating
the two brain hemispheres.
• Once the brain was separated scientists
could learn a lot about each, individual
hemisphere.
http://www.youtube.com/watch?v=ZMLzP1VCANo&feature=related
Did you see a man or a
woman?
One way to determine brain
hemisphere dominance…
• One way that some people think you can
determine brain hemisphere dominance is
by studying the irises of the eyes.
• Work with a partner to examine each
others’ eyes
• Use the images on the next two pages to
figure out your brain dominance.
A right-brain dominant Jewel
structure
notice there are
more/larger/stronger brown dots
(jewels) in the left iris indicating
more activity in the right
hemisphere.
Right Eye Left Eye
A right-brain dominant Flower
structure
notice there are more/larger/stronger
fibre petals (flowers) in the left iris
indicating more activity in the right
hemisphere.
A left-brain dominant
Jewel structure
notice there are
more/larger/stronger jewels in
the right iris indicating more
activity in the left hemisphere.
Right Eye
Left Eye
A left-brain dominant
Flower structure
notice there are
more/larger/stronger
flowers in the right iris
indicating more activity in
the left hemisphere.