Transcript The Brain

Chapter 2
Part II
THE BRAIN
How We Study the Brain
How We Study the Brain…
I.
Non Technological Methods:
A. Prior to technology, BRAIN DAMAGE was the
one way to understand what each part of
the brain did.
*
“Tan” – Language Centers of Brain
Phineas Gage

http://www.learner.org/r
esources/series142.html?
pop=yes&pid=1592#
How We Study the Brain
B.
Psycho-Surgery – Removal of brain tissue or
structures leads to an understanding of those
cells/structures. (tumors/elective)
1. Lesion: - Removal of specific
cells/neurons
2. Lobotomy: - Severing of the connection
between the limbic system and the prefrontal cortex. Used in 1940’s to “treat”
people. Furthered understanding of
these brain structures. No longer used for
“treatment” because it didn’t work.
How We Study the Brain
II.
With the help of technology
A.
Microelectrode Techniques: (Penfield/Delgado
Motor/Sensory Cortex Maps)
They detect impulses from AN ELECTRODE and follow
it through the body to the brain or brain to body.
B.
Electroencephalagraph EEG
Traces CHARGES produced by IONS by filtering out
everything but the electrical wave created by an
outside stimulus.
C.
Computerized Axial Tomography C/T or CAT SCAN
Still-life TWO-DIMENSIONAL photo of the brain.
Electrode Probing
CT/CAT Scan
EEG: electrical activity
How We Study the Brain
D.
Magnetic Resonance Imaging (MRI)
A person’s head is placed in a MAGNETIC FIELD
where ATOMS are disoriented by brief PULSES . When
atoms return to normal, they emit SIGNALS -- a
computer generates images of the soft tissue from
these signals.
1. fMRI (Functional MRI)
Watch the video clip about brain imagining
and write a brief description about how this
works.
MRI
MRI: detailed pictures
How We Study the Brain
E.
Positron Emission Tomography (PET SCAN)
Our brains consume GLUCOSE (sugar) when active.
An individual is INJECTED with a low dose of
RADIOACTIVE sugar. The scanner then shows full
COLOR of each area of the BRAIN that consumes
the radioactive sugar by burning it. Actually picks
up the HEAT rays emitted by the cells when they
burn the glucose.
PET scan: glucose burn
PET Scan
Overview of the Brain
The brain is divided into three regions.
A.
The Hindbrain
1.
Sub-Cortex (left hand):

The “OLD BRAIN”, Hindbrain

These structures are the earliest to EVOLVE according to evolutionary
psychologists. The sub-cortex is made up of structures that control our
BASIC needs such as INSTINCTS, EMOTIONS and INVOLUNTARY
responses.
B.
The Midbrain
C.
The Forebrain
1.
Cerebral Cortex(right hand):

The “NEW BRAIN”, Cerebrum

This is the upper, WRINKLED layer of the brain divided into two
HEMISPHERES and four LOBES. The cerebrum is made up of structures
that influence upper level functioning such as LOGIC, LANGUAGE,
LONG-TERM MEMORY and ABSTRACT thought.
Divisions of Brain
Diagram 1
Overview of the Brain
C. Matter:
1.
White
Myelinated neurons
of CNS
vs.
2.
Gray
Non-Myelinated
neurons of CNS
Overview of the Brain
D. Fissures/Wrinkles
1.
Longitudinal
Separates
hemispheres (L/R)
2.
Central
Separates frontal
lobes from parietal
lobes
3.
Lateral
Separates frontal
and parietal lobes
(top) from temporal
lobes (bottom)
Overview of the Brain
E. Systems:
1. Nervous
Neurons/Neurotransmitters
ex. Frontal Lobes/Dopamine
vs.
2. Endocrine
Glands/Hormones
ex. Adrenal Glands – Adrenaline

Overview of the Brain

Brain Structure Notes

Song Break

Brainstem!
The Hindbrain/Sub-Cortex
Structures
A. Brain Stem(arm):
Extension of the spinal cord into the BRAIN.
Approximately 3 INCHES long. Controls AUTONOMIC
functions such as:
B. Medulla(tap/cross wrists):
Nearest structure to the brain stem. 1.5 inches long.
Controls BREATHING, heart rate, blood pressure, and,
most importantly, this is the sensory and motor
CROSS-over station.
The Hindbrain/Sub-Cortex
Structures
C.
Pons(yawn):
This structure works with the PINEAL body to regulate SLEEP
and WAKE cycles (circadian rhythm) by stimulating the
release of SEROTONIN. It also communicates between the
CEREBELLUM and the MOTOR CORTEX to help regulate
balance and posture.
D.
Pineal Body(yawn):
A part of the ENDOCRINE system. Releases the hormone
MELOTONIN Works with the pons to regulate sleep/wake
cycles. Controlled by LIGHT and DARK environments.
Reflect: How do your own sleep habits relate to the
information you’ve learned about the pons and pineal gland?
Structures of the Hindbrain
and Midbrain
E.
Midbrain:
Several structures in the middle of the subcortex that are related to PAIN sensations.
F.
Thalamus - Thala MAIL amus (pass the mail):
Sends FILTERED sensory information to the CEREBRAL cortex to
be interpreted by these higher-level portions of the brain.
Works as a SENSORY relay station.
G. Reticular Formation(snap/tic):
Also called the RETICULAR ACTIVATING SYSTEM. Filters
incoming sensory information to send it to the THALAMUS
Related to mental AROUSAL and the ability to focus attention.
Structures of the Hindbrain
and Midbrain
H.
Cerebellum(back of wrist):
Also called the “LITTLE” brain because it is wrinkled like the fissures
of the cerebral cortex. Located behind the BRAINSTEM under the
OCCIPITAL lobe.
Related to BALANCE, posture, and VOLUNTARY movement.
I.
Corpus Callosum:
Large band of AXONS that communicate between HEMISPHERES
of the cerebral cortex. Many INTERNEURONS that relay
information back and forth.
J. Pituitary: Another GLAND that secretes HORMONES rather
than NEUROTRANSMITTERS. Known as the MASTER gland. This
gland stimulates the other glands throughout the body to function
when necessary. It also releases GROWTH hormone that regulates
development early in life.
The Sub Cortex/Hindbrain–
Diagram 2
Hindbrain Structures –
Diagram 3
Structures of the Hindbrain
and Midbrain
K. The Limbic System:
THE EMOTIONAL Brain
(heee heee, whaaaa!!!, grrrrr!!)
Made up of three structures. Associated with
basic emotions, basic drives, and basic memory
formation.
1. Hippocampus:
Center of MEMORY. Initial formations occur
here for EPISODIC (personal) and SEMANTIC
(factual) memories.
Structures of the Hindbrain
and Midbrain
2.
Amygdala(pinky/thumb):
Related to experiences of AGGRESSION and fear. Two
basic emotions. Not the center of PROCESSING these
emotions, though. FIGHT OR FLEEEEEE…. (by activating
the hypothalamus)
Reflect: What is your favorite brain part so far?
3.
Hypothalamus:
Right below the THALAMUS. Controls and regulates
your basic DRIVES such as HUNGER, THIRST, and
sexuality. It is considered to be your PLEASURE center.
Forebrain Structures –
Diagram 4
The Limbic System

Electrode
implanted in
reward center

http://www.learne
r.org/resources/ser
ies150.html?pop=y
es&pid=1613
..\BRAIN_SONG\BRAI
NSNG.WAV
The Cerebral Cortex
The Cerebral Cortex
The Cerebral Cortex:

“NEW” Brain

TWO Hemispheres

FOUR Lobes

16 square feet

FISSURES (wrinkles)
(17 – 23 pieces of paper laid out flat)
The Cerebral Cortex
F(lower) P.O.T.
Frontal Parietal Occipital Temporal
OR
F(reud’s) M(other) S(mokes) P.O.T
Frontal
(motor)
(sensory)
Parietal
Occipital
Temporal
Frontal Lobes
Behind forehead
1. Pre-frontal
a. Personality, processing of emotions,
abstract thought, logic, judgment
2. Motor Cortex (on frontal lobe)
a. Speech production and muscle
movement
b. Axons cross over at the MEDULLA.
c. Mapped for all muscle movement
Parietal Lobes
Behind Motor Cortex. Center/Top
1. Sensory Cortex (on parietal lobes)
2. Mapped for all skin sensations
3. Cross over at MEDULLA.
Occipital Lobes
Back of Cerebrum/Above cerebellum
1. VISUAL Cortex
2. Center of all visual processing
The Cerebral Cortex

Functional MRI scan
shows the visual cortex
activated as the
subject looks at faces
Temporal Lobes
Behind temples
1. AUDITORY Cortex
2. Memory processing, facial recognition,
understanding speech
Association Areas
1. Areas within the brain that communicate
using interneurons.
2. Full of NEURAL Networks, or series of connected
neurons that connect at the synapse and grow
in strength as you practice and/or learn.
Association Areas

More intelligent animals have increased
“uncommitted” or association areas of the cortex
Diagram 5
Language Centers
1. Broca’s Area: Broca/Boca
Works with muscles, face and jaw to produce speech.
Located in left, frontal lobe.
If it’s damaged, we can’t SPEAK.
2. Wernicke’s Area
Works to help us understand language. Located in
left, temporal lobe.
If it’s damaged, we can’t COMPREHEND.
3. Angular Gyrus:
Responsible for turning written words into auditory form
so that we can read language. Located between
Wernicke’s and the Occipital Lobes in left hemisphere.
If it’s damaged, we can’t READ.
Language Centers –
Diagram 5
Language Centers

Brain activity when hearing, seeing, and speaking
words
Tan

http://www.learner.org/resources/series142.html?pop=yes&pid=1574 – choose #6

The Cerebral Cortex

Aphasia


Broca’s Area (Disrupts speaking)


impairment of language, usually caused by left hemisphere
damage either to Broca’s area (impairing speaking) or to
Wernicke’s area (impairing understanding)
an area of the left frontal lobe that directs the muscle movements
involved in speech
Wernicke’s Area (Disrupts understanding)

an area of the left temporal lobe involved in language
comprehension and expression
Sensory/Motor
Right and Left Brain

Which diagram
(from the handout)
“spoke” to you?
Our Divided Brain
Corpus callosum

Corpus Callosum

large band of
neural fibers

connects the two
brain hemispheres

carries messages
between the
hemispheres
Split Brain




a condition in which the two
hemispheres of the brain are
isolated by cutting the
connecting fibers (mainly those
of the corpus callosum) between
them
Roger Sperry
Michael
Gazzaniga
http://www.youtu
be.com/watch?v=
aCv4K5aStdU
The Endocrine System

Endocrine System

Chemical messengers are
hormones, rather than
neurotransmitters

Messages travel through
the bloodstream
Diagnosis BRAIN!!
WHAT PART(S) OF THE BRAIN
ARE DAMAGED?
DISCUSS AND EVALUATE AS A
TEAM USING YOUR NOTES,
KNOWLEDGE, AND SUPER
DUPER ASSOCIATION AREAS.
Mr. Livingston

Mr. Livingston is a 39 year-old
African-American male who has
been brought into your
neurology clinic by his wife. She
has become increasingly
alarmed regarding her
husband’s health over the past
four months. Upon completion
of CT scans, it is determined that
Mr. Livingston’s condition is the
result of the presence of two
tumors that have developed in
his brain. Using this patient’s
medical history below,
determine where these two
tumors are probably located.
Mr. Livingston’s Symptoms
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Muscle weakness
Vastly increased appetite (gained 25 lbs)
Inappropriate body temp fluctuations
Jerky movements
Decreased sexual desire
Poor balance when walking and standing
Increased urination
Inability to throw objects
Inappropriate sleeping patterns
Exaggerated efforts to coordinate
movements when completing a task.
Shooting Victim

At 1:30 a.m. you (a trauma surgeon)
are called for emergency surgery on
a 17 year old Caucasian female that
was shot in the head during a driveby shooting. After tedious surgery,
the patient remarkably remains alive
and doing reasonably well. The
bullet traveled completely through
the skull leaving a path of destroyed
tissue behind. You have decided to
speak with the parents about what
noticeable changes will occur in their
daughter due to the destruction of
the neural tissue. Based on the
information below, determine the
approximate path the bullet traveled
(i.e., what structures were damaged).
Symptoms

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Limb numbness
Inability to control movement in the left
shoulder, arm, forearm, and hand.
Slow, laborious, nonfluent speech
Inability to sound out words
Difficulty finding appropriate words to
use
Irrational anger
Easily startled and irritated by loud
noises
Reacts fearfully to sudden movements
or changes in her environment
Norman Folger

You are a pathologist in a
large northwestern city.
You are conducting the
autopsy on an 83 year-old
male who was found dead
in his home with no obvious
cause of death. During the
autopsy you discover the
individual suffered two
strokes. Based on the
functional information
below provided by the
next-of-kin, where were the
areas damaged by the
stroke?
Norman’s Symptoms
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Failure to do certain, specific movements
Massive overeating
Disrupted circadian rhythms
Increased susceptibility to stress
Poor muscle tone
Inability to adjust heart rate
Inability to focus attention
Unrestricted water loss in kidneys
Inability to recognize faces
Temperature fluctuations
Memory disruption
Hearing loss
THE ANSWERS!!! 
1.
Cerebellum, Pons, Motor Cortex Hypothalamus
2.
Primary Motor Cortex(right hemisphere), Brocas
Area, Amygdala
3.
Hypothalamus, Reticular Formation, Temporal
Lobes