The Brain
Structures, Functions, and Injuries
The Brain


“Older” brain networks sustain
______________ functions, and enable
memory emotions, and basic drives
Newer neural networks within the cerebrum –
the two large hemispheres that contribute 85%
of brain’s weight  are associated with:
Perceptions, Thinking, Speaking
The Cerebral Cortex

Cerebral Cortex: a thin surface layer of
interconnected neural cells, covers cerebrum
“Brain’s Thinking Crown”
 Ultimate control and information-processing center


How does our cerebral cortex separate us from other
animals?
Structure of the Cortex

Cerebral Cortex: contains 20-23 billion nerve
cells – 300 trillion synaptic connections

Glial Cells: cells that support, nourish, and protect
neurons
Neurons = Queen Bees
 Glial Cells = __________

Structure of the Cortex

Each brain
hemisphere is divided
into four lobes that
are separated by
prominent fissures.

These lobes are the:




___________ lobe
(forehead)
__________lobe (top to
rear head)
________ lobe (back of
head)
__________ lobe (side of
head).
The Cerebrum:
Two Hemispheres, Four Lobes

Four Lobes: each lobe carries out many functions
and many functions require interplay of several
lobes



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Occipital – associated with visual processes
Parietal –associated with sensory input for touch and
body position
Temporal – hearing and balance
Frontal – muscle movement, decision-making,
planning, & speaking

Responsible for the ability to “see” or be aware of ourselves, reexperience past events, come up with strategies or plans,
interpret what is going on in the world around us, and tell us
what to do and feel.
Motor Functions

1870, Fritsch &
Hitzig
Electrical stimulation
to parts of a dog’s
cortex
 Could make parts of
body move

Stimulating parts of this
region in left or right
hemisphere caused
movements of body
parts on opposite side
of the body
 Discovered motor
cortex: area at rear of
frontal lobes that control
voluntary movements

Functions of the Cortex

The Motor Cortex is the area at the rear of the
frontal lobes that control voluntary movements.


___________ messages out to the body
The Sensory Cortex (parietal lobe) __________
information from skin surface and sense
organs.
Sensory Cortex

Sensory cortex:

Area at the _______ of the parietal lobes
Registers and processes body touch and movement
sensations
 If neurosurgeons stimulate point:



On top of this band of tissue, a person may report being
touched on the ____________
On side of this band of tissue, a person may report being
touched on their ___________
Sensory Cortex

Sensory cortex:
There are various areas in brain where cortex
receives input from
 Visual information in visual cortex in occipital
lobes, at the _________ of your brain


Bash in the back of your head can make you ___________or
stimulating it you might see flashes of color
Association Areas

Association Areas: areas of cerebral cortex,
involved in higher mental functions such as:
.
 .
 .
 .

Association Areas

Association Areas:

Not involved in primary motor or sensory function
Account for _____ of cerebral cortex
 Link sensory inputs with stored memories
 Interpret, integrate, and act on information
processed by sensory areas

Association Areas

Association Areas:
Found in all four lobes:
 Frontal Lobes: association areas enable
judgment, planning, and processing of new
memories


Which of these would damage to frontal lobe affect?




Intact Memories
Planning ahead to bake a cake
High Scores on IQ tests
Cake baking skills
Association Areas

Frontal lobe damage can also alter personality:
Removing inhibitions
 Moral judgments unrestrained


Phineas Gage
Effects of Other Brain Injuries:
Phineas Gage
Gage
was a railroad
construction foreman
An 1848 explosion forced a
steel tamping rod through his
head
Others said he was “no
longer Gage”
Lost his job, worked as a
sideshow exhibit
Gage’s Injuries and Symptoms




The rod pierced through his frontal lobe and exited out
the top of his skull.
Remarkably enough, he survived because none of the
vital parts that control breathing, movement or physical
control had been damaged.
However, other major changes were noticed as a result
of the accident. Gage, a usually friendly and normal
person, suddenly began to swear frequently,
undress whenever he felt like it, urinate in public,
and have temper tantrums.
The case of Phineas Gage suggests that our frontal
lobe plays a large part in social control and
personality, and demonstrates the severe effect any
type of brain injury can have.
Phineas Gage video link
(#25):
http://www.learner.org/reso
urces/series142.html
Figure 2.28 Phineas Gage reconsidered
Myers: Psychology, Ninth Edition
Copyright © 2010 by Worth Publishers
Association Areas

Must be wary of using pictures of brain “hot
spots” that locate complex functions in precise
brain areas
Parietal Lobes: enable mathematical & spatial reasoning
 Temporal Lobes: facial recognition


Prosopagnosia
Very complex mental functions DO NOT reside
in any one place
 Memory, language, attention result from
synchronized activity among distinct brain
areas

Language
•
Aphasia is an impairment of language, usually
caused by left hemisphere damage either to
Broca’s area (impaired speaking) or to
Wernicke’s area (impaired understanding).

Broca’s Area




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Receives impulse from Wernicke’s
Area and converts it into motor
commands.
Damage: disrupts speaking
Person can understand language
Words may not be properly formed
Speech is slow and slurred.
Patients may get frustrated because
they know that something is wrong.

Wernicke’s Area





The area in our brain that allows
understanding of spoken and written
language.
It is the part that enables a person to
interpret language, so damage to this part
causes the person to become unaware of his
own speech and the speech of others.
Sometimes the person can speak clearly, but
the words that are put together make no sense.
This way of speaking has been called "word
salad" because it appears that the words are
all mixed up like the vegetables in a salad.
Might use complete nonsense words.
Often not aware of their problem.