Transcript Research Methods

Research Methods
Psychology 2617
Or, so how do we know this stuff
We can look at the whole brain
 We can look at parts thereof
 We can look at neurons
 We can look at synapses
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neurons
Even before electron microscopes, we
could look at neurons thanks to Golgi
 He discovered that when stained with
Silver chromate, neurons went black
 Today we call this golgi stain
 Led to the classification of neurons, as we
could finally see their physical properties
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Stains are not always bad
Golgi stain does not show number of
neurons in a region that well though
 It stains just a few
 Nissl Used dyes!
 Methelyne blue
 Myelin staining
 HRP and axonal transport allow us to see
circuits!
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Radiation, run for your lives!
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X Rays are cool, but,
they don’t work well
on brains
AEG, kinda
dangerous
CAT scans are cool
though
Gives us a good idea
about form
Some of this stuff is a little, oh
yucky
Angiography
 Wada technique
 Both involve injections into the blood
supply of the brain while the patient is
awake
 Wada technique proved once and for all
the idea of hemispheric specialization
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EEG
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Electroeds placed on
the head
Brain waves
Gamma activity is fast and big, peak
activity
 Beta low amplitude but fast, being alert
 Alpha quiet
 Theta quiet, sleep
 Delta super slow, deep sleep
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Diagnostic uses of EEG
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Epilepsy is associated
with crazy EEGs
Basically
uncontrollable firing
Spreads can lead to a
seizure
Evoked potentials
Stimulus given
 Basically computer subtracts out the
background EEG
 Used lots in research and in diagnostic
areas
 Some disorders show characteristic ERPs
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Electrical Brain stimulation
Basically put an electrode in the brain with
the patient awake
 The classic Dr. Penfield approach
 Not nearly as effective as Penfield made it
out to be…
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Looking at metabolism
Blood flow techniques
 Use radioactive isotopes
 Look for anomalies
 SPECT sort of a poor mans….
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PET scan
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Positron emission
tomography
MRI
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Magnetic Resonance
Imaging
MRI
Basically a combo of RF signals and a
REALLY strong magnetic field
 Has no ill effects, unless you have a metal
plate in your head
 Shows form and function
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Behavioural techniques
These are really the kind of thing that
involve say, touching your nose
 Or presenting a stimulus to one visual field
and not the other
 Really quite telling, but nowadays you then
end up in an MRI often
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Advances
Basically the imaging techniques remain
the same
 It is the computing power and software
that is allowing for real time analysis that is
having the biggest effect
 When MRI first came out the fastest
desktop computer was MAYBE running a
75 MHz
 This little powerbook runs at 1.25 Ghz
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