1 psychology (8th edition, in modules) david myers jessica mulder worth publishers, © 2007
TRANSCRIPT
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PSYCHOLOGY(8th Edition, in Modules)
David Myers
Jessica Mulder
Worth Publishers, © 2007
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The Brain
Module 5
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The Brain
Techniques to Study the Brain
Brain lesion experimentally
destroys brain tissue to study animal behaviors after such destruction.
Hubel (1990)
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Clinical ObservationClinical observations have shed light on a
number of brain disorders. Alterations in brain morphology due to neurological and
psychiatric diseases are now being catalogued.
Tom
Landers/ B
oston Globe
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Electroencephalogram (EEG)An amplified recording of the electrical waves
sweeping across the brain’s surface, measured by electrodes placed on the scalp.
AJ P
hoto/ Photo R
esearchers, Inc.
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PET Scan
PET (positron emission tomography) Scan a visual display of brain activity that detects a radioactive form of glucose while the brain performs a
given task.
Courtesy of N
ational Brookhaven N
ational Laboratories
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MRI ScanMRI (magnetic
resonance imaging) uses magnetic fields and
radio waves to produce computer-generated
images that distinguish among different types of brain tissue. Top images
show ventricular enlargement in a
schizophrenic patient. Bottom image shows brain regions when a
participants lies.
Both photos from Daniel Weinberger, M.D., CBDB, NIMH
James Salzano/ Salzano Photo Lucy Reading/ Lucy Illustrations
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Older Brain Structures
Brainstem the oldest part of the brain, beginning where the spinal cord swells and enters the skull.
Responsible for automatic survival functions.
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Brain Stem
Medulla [muh-DUL-uh] base of the
brainstem, controls heartbeat and
breathing.
Reticular Formation a nerve network in the brainstem that plays an important role in controlling arousal.
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Brain Stem
Thalamus [THAL-uh-muss] the brain’s
sensory switchboard, located on top of the brainstem. It directs
messages to the sensory areas in the cortex and transmits
replies to the cerebellum and
medulla.
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The “little brain” attached to the rear of the brainstem. It
helps coordinate voluntary movements
and balance.
Cerebellum
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Limbic System a doughnut-shaped system of neural
structures at the border of the brainstem and cerebrum, associated with emotions such as fear, aggression and
drives for food and sex. It includes the hippocampus, amygdala, and hypothalamus.
The Limbic System
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Amygdala
Amygdala [ah-MIG-dah-la] two almond-
shaped neural clusters linked to emotion of
fear and anger.
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Hippocampus
• Structure of the limbic system that is linked to memory.
• Memory Device: hippo= big campus= place where you learn/remember.
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Hypothalamus
Hypothalamus lies below (hypo) the thalamus; directs
several maintenance activities like eating,
drinking body temperature, and emotions. Helps
govern the endocrine system via the
pituitary gland.
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Rats cross an electrified grid for self-
stimulation, when electrodes are placed
in the reward (hypothalamus) center (top picture). When the
limbic system is manipulated rat will
navigate fields or climb up a tree (bottom
picture).
Reward CenterS
anjiv Talw
ar, SU
NY
Dow
nstate
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The Cerebral Cortex
The intricate fabric of interconnected neural cells that covers the cerebral hemispheres. The body’s
ultimate control and information processing center.
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Structure of the Cortex
Each brain hemisphere is divided into four lobes, separated by prominent fissures.
They are frontal lobes (forehead), parietal lobes (top to rear
head), occipital lobes (back head) and
temporal lobes (side of head).
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Functions of the Cortex
Motor Cortex area at the rear of the frontal lobes controls voluntary movements. Sensory Cortex (parietal cortex) receives information
from skin surface and sense organs.
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Visual Function
Functional MRI scan shows the visual
cortex activates as the subject looks at faces.
Courtesy of V
.P. Clark, K
. Keill, J. M
a. M
aisog, S. Courtney, L
.G.
Ungerleider, and J.V
. Haxby,
National Institute of M
ental Health
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Auditory Function
Functional MRI scan shows the auditory cortex is activate in
patients who hallucinate.
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More intelligent animals have increased “uncommitted” or association areas of the
cortex.
Association Areas
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LanguageAphasia 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).
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Specialization & Integration
Brain activity when hearing, seeing, and speaking words
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Brain is sculpted by our genes but also by our experiences.
Plasticity refers to the brain’s ability to modify itself after some type of injury or illness.
The Brain’s Plasticity
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Our Divided Brain
Our brain is divided into two hemispheres. Left hemisphere processes reading,
writing, speaking, mathematical, comprehension skills, and thus termed as
the dominant brain in the 1960s.
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Splitting the BrainA procedure in which the two hemispheres of the brain are isolated by cutting the connecting fibers
(mainly those of the corpus callosum) between them.
Corpus Callosum
Ma
rtin M
. Ro
the
r
Courtesy of T
erence William
s, University of Iow
a
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Split Brain Patients
With the corpus callosum severed, objects (apple) presented in the right visual field can be named.
Objects (pencil) in the left visual field cannot.
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Divided Consciousness
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Try This!
Try drawing two shapes with both of you hands simultaneously.
BB
C
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Non-Split Brains
People with intact brains also show left-right hemispheric differences in mental abilities.
A number of brain scan studies have shown normal individuals engage their right brain when they engage in a perceptual task, and
left brain when carrying out a linguistic task.