Transcript How Psychologists Study the Brain

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Also called psychobiologists
Psychologists who map the brain’s fissures
(grooves on the brain which appear as a deep fold)
and inner recesses
Methods include:
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Recording
Stimulating
Lesioning
Imaging
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Electrodes inserted into the brain to record
electrical activity
◦ Recall the brain generates enough electricity to
power a low-wattage light bulb!
Possible to detect minute (small) electrical changes
that occur when neurons (brain cells)
fire
EEG (electroencephalograph) records
electrical activity of whole areas of
the brain
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Have found that overall electrical activity of the
brain rises and falls rhythmically and that the
pattern of the rhythm depend on whether a person
is awake, drowsy, or sleepy
Rhythms(brains waves), occur because the neurons
in the brain tend to increase or decrease their
amount of activity in unison (together)
Electroencephalogram (EEG) –a
device that records the electrical
activity of the brain.
Scans • Computerized Axial Tomography (CAT
or CT) detect brain damage & measure
activity as subjects perform a task.
Fast Fact - Acupuncture
is based on the belief that by inserting
needles into various parts of the body, they can interrupt pain
messages sent to the brain, thus alleviating the pain or treating the
illness
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Electrical Stimulation -Electric stimulation of one part
of the brain causes specific sensations in the body.
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Electrodes used to set off (cause) the firing of neurons
(brain cells)
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Brain surgeon Wilder Penfield stimulated the brains of
his patients during surgery to determine what
functions the various parts of the brain perform so as
to localize (focus on) the malfunctioning part for which
surgery was required
https://www.youtube.com/watch?v=68MiW2KK1us
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Stimulation techniques have
been used with terminal cancer
patients to relieve intolerable
pain without using drugs and in
experiments done to control
violent emotional behaviours in
uncontrollable patients
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Scientists sometimes create lesions by cutting or
destroying parts of an animal’s brain.
If the animal behaves differently after the
operation, they assume that the destroyed brain
area is involved with that type of behaviour
Psychologists can learn from tragedies when some
people suffer accidents which involve the brain.
They can see the results of physical brain damage
& its affects on people.
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Psychobiologists try to draw a connection between
the damaged parts of the brain and a person’s
behaviours, such as Phineas Gage in 1848
P H I N E A S
G A G E
Students write down the following questions in your notes. Write your
answers in complete sentences.
What type of scanning
device is used to
analyze Gage’s brain?
What part of Gage’s
Brain was damaged?
How did Phineas Gage
change after the
accident?
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Psychobiologists use PET scans, CAT scans and MRI
scans
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Means Positron emission tomography
Captures a picture of the brain as different parts
are being used
Involves injecting a slightly radioactive solution
into the blood and then measuring the amount of
radiation absorbed by brain cells
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Active neurons absorb more radioactive solution
than a nonactive one
Used to see which areas are being activated while
performing a task
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About 1 hour after the injection, the PET scan is done.
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The PET scanner looks like a large, doughnut-shaped scanner,
similar to a CT scanner.
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The person sits or lies down on the exam table and is asked to
stay very still.
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Sometimes PET scan can be done along with CT or MRI.
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After the scan, the radioactive material quickly loses its
radioactivity. It passes out of the body through the urine or stool
(feces)
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Means computerized axial tomography
Used to pinpoint injuries and other problems in
brain deterioration (ex. Alzheimer's Disease)
During scan, a moving ring passes x-ray beams
around and through a subject’s head
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Radiation is absorbed in different amounts
depending on the density (“weight”) of the brain
tissue
Computers measure the amount of radiation
absorbed and transform this information into a
three-dimensional view of the brain
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A computed tomography (CT) scan is an imaging test that uses a
computer to put a series of special x-ray images together to
create detailed 3-dimensional images of organs, tissues, bones
and blood vessels in the body. Some CT scans require a contrast
medium to show organs and abnormalities more clearly.
A CT scan is also called computerized axial tomography (CAT)
scan.
A CT scan can be done on almost any body part. It can show
detailed views of many different types of tissue, such as the:
brain, airways, lungs, bones, soft tissue and blood vessels
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Means magnetic resonance imaging
Enables researchers to study both activity and
brain structures
Combines features of both PET and CAT scans
Involves passing nonharmful radio frequencies
through the brain
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A computer measures how these signals interact
with brain cells and translates these signals into a
detailed image of the brain
Used to study the structures of the brain as well as
to identify tumours or types of brain damage
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A magnetic resonance imaging (MRI) is an imaging test that uses
powerful magnetic forces and radio-frequency (RF) waves to
make detailed 3-dimensional pictures of organs, soft tissues,
bone and most other internal body structures. Some MRI scans
require a contrast medium to provide clearer images.
Different tissues react differently to the magnetic current and this
produces various images. No ionizing radiation is used in MRI.
MRI cannot be done if the person has certain metal devices inside
their body (such as a pacemaker, implanted port or pump). The
magnetic force is so strong that it can damage or dislodge these
devices. In most cases, MRI can be done on people who have joint
replacements, surgical clips or screws.
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Means functional
magnetic resonance
imaging
Can directly observe
both the functions of
different structures of
the brain and which
structures participate in
specific functions by
recording the movement
of blood flow
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How Does an MRI Work? (1:21)
http://www.youtube.com/watch
?v=1CGzknV06g&list=PL1872FCF16467E
980
How Does a PET Scan Work?
(1:33)
http://www.youtube.com/watch
?v=GHLBcCv4rqk&feature=c4overviewvl&list=PL1872FCF16467E980
How CT Scan Machine Works
(1:01)
http://www.youtube.com/watch
?v=tqGmqRrxajQ