Transcript Unit 3A - The Brain PowerPoint

The Brain
The Brain
• Made up of neurons
• 23 billion nerve cells
and 300 trillion
synapses
• Glial cells –
My husband is my glial cell.
He takes care of me!!!
Whose yours?
Ways we Study the Brain
Accidents
Phineas Gage
• Personality changed
after the accident.
What did this tell us?
• That different part
of the brain control
different aspects of
who we are.
Lesions
• Frontal
Lobotomy
Electroencephalogram
• EEG
• Detects brain
waves through
their electrical
output.
• Used mainly in
Computerized Axial Tomography
• CAT Scan
• 3D X-Ray of
the brain.
Magnetic Resonance Imaging
• MRI
Positron Emission Tomography
• PET Scan
Functional MRI
• Identifies most active areas of the brain
during a specific mental task
Brain Structures
• Scientists divide the
brain up into three
parts.
Brain Regions
• Brainstem
•
•
• Limbic System
• Cerebral Cortex
Brain Regions
• Hindbrain
• Midbrain
• Forebrain
Brain Stem
• Part of the brain with the
oldest ancestry
• 3 Parts:
– Medulla
– Pons
– Reticular formation
Limbic System
• EMOTIONAL CONTROL
CENTER of the brain.
• REWARD CENTER of the
brain (hypothalamus)
• Located between the
brainstem and cerebral
hemispheres
• Made up of Hypothalamus,
Amygdala and Hippocampus.
Areas of the Cerebral Cortex
• Divided into eight
lobes, four in each
hemisphere
Figure 3B.13 Left hemisphere tissue devoted to each body part in
the motor cortex and the sensory cortex As you can see from this
classic though inexact representation, the amount of cortex devoted to a
body part is not proportional to that part’s size. Rather, the brain devotes
more tissue to sensitive areas and to areas requiring precise control.
Thus, the fingers have a greater representation in the cortex than does the
upper arm.
Association Areas
• Locate in cerebral cortex
• Not directly involved in sensory
and motor activity (sensory
cortex, motor cortex, visual
cortex or auditory cortex)
• Involved in higher mental
functions such as
• Example:
Figure 3B.16 Areas of the cortex in four mammals
More intelligent animals have increased
“uncommitted” or association areas of the cortex. These
vast areas of the brain are responsible for integrating and
acting on information received and processed by sensory
areas.
© 2011 by Worth Publishers
Language Development
• Aphasia –
• Frontal Lobe
– Broca’s Area –
• Temporal Lobe
– Wernicke’s Area –
• Parietal Lobe
– Angular Gyrus –
The Divided Brain
• Plasticity –
• .
• The younger you are, the more plastic your
brain is.
• Contraint induced therapy - teaching a
patient to regain the use of an impaired limb
by limiting the use of the good limb
• Neurogenesis –
What can you do to
produce
new neurons?
Hemispheres
• Brain Lateralization divided into a left and
right hemisphere.
• Contralateral
controlled- left controls
right side of body and
vice versa.
• Left Brain –
• Right Brain –
Split-Brain Patients
• Sperry and Gazzaniga
• Corpus Callosum –
connects two brain
hemispheres and carries
messages between them
• Removed in patients with
severe epilepsy
• When removed you have a
split-brain patient.
Figure 3B.22 The information highway from eye to
brain
Information from the left half of your field of vision
goes to your right hemisphere, and information from the
right half of your visual field goes to your left
hemisphere, which usually controls speech. (Note,
however, that each eye receives sensory information
from both the right and left visual fields.) Data received
by either hemisphere are quickly transmitted to the other
across the corpus callosum. In a person with a severed
corpus callosum, this information sharing does not take
place.
© 2011 by Worth Publishers
Figure 3B.23 Testing the
divided brain When an
experimenter flashes the word
HEART across the visual field, a
woman with a split brain
However, if asked to indicate
with her left hand what she saw,
.
From Gazzaniga, 1983
Figure 3B.25 Which one is happier? Look at
the center of one face, then the other. Does one
appear happier?
The Brain and Consciousness
• Consciousness –
• Dual Processing –