Introduction to Physiological Research Methods

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Introduction to Physiological Research Methods

• Kimberly Anderson
• 392-0601, ext. 215
• Linkette_at_fastmail.fm

Last given 2-4-04
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Changes to the class

• Less on the slides, need to take more notes
• Ill try to talk slower
• May be quizzes at the end of class
• A lot more short videos, so come to class!
• Why am I giving this lecture?

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What is a physiological measure?

• What is it?
• An internal process that can be measured.
• Ex. Heart rate, EEG, blood flow (spec. to the
  brain).
• What is it used for?
• To gain more insight into what is going on while
  the participant is doing the task.
• Brain/behavior relationship

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Why not just behavioral research?

• 1. Children are not very good at talking about
  their actions.
• Example Paying attention or difficulty
• 2. Allows us to get information about the
  participant during the task, not just afterwards.
• 3. What area of the brain handles what?
• If using physiological, always use behavioral

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Why dont we always use physiological measures?

• Some of the measures are very expensive
• Not all measures can be taken in the field
• Takes a long time set-up
• Lot harder to have the children participate
• Limits the type of research you can do
• So why does ANYONE do it?!

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Outline of Todays Lecture

• Heart Rate/Vagal Tone
• EEG/ERP
• Electroencephalogram
• MRI
• Magnetic Resonance Imaging
• fMRI
• Functional Magnetic Resonance Imaging
• PET
• Positron Emission Tomography

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Heart Rate Variability
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Heart Rate Variability

• How do you measure HRV?
• 2 Components
• Heart Rate (Electrodes across the chest)
• Respiration - (Band around the chest)
• How to use HRV in research
• Level of synchrony of respiration and heart rate.

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HRV Example

• How is HRV affected by task difficulty?
• Example Video Games
• During easy level
• HR and RESP in synch
• During hard level
• HR and RESP out of synch

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HRV in Developmental Research

• Normal Stroop task
• What does this measure?
• Does not require reading
• Control vs. Experimental conditions
• What would
• HRV look like?

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Day Night Stroop Task
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Great Job!!
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Electroencephalogram (EEG) Event-Related
Potentials (ERP)
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What is EEG/ERP?

• Measures activity of the brain by picking up the
  electrical signal.
• The electrode cap has electrodes on it that pick
  up this signal from certain areas of the brain.

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What is EEG?

• Each dot is an electrode
• Blue is negative, red is positive

Front
Back
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Child and Adult Brain Activity
Frontal
Parietal
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Using EEG/ERP in Developmental Research

• Noninvasive
• Use with infants up to older adults
• Differences in activation of children and adults.

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Advantages and Disadvantages

• Advantages
• Tell which brain areas are active
• Great temporal resolution
• Relatively Inexpensive
• Limitations
• Poor spatial
  resolution
• Long set-up time

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Magnetic Resonance Imaging
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MRI
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Basics of the brain

• Lot of water in it
• Water has protons in it which are polarized
• When something is polarized, you can make it turn
  one direction with a magnet.
• Use magnets to influence direction of proton
  directions in brain.

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What is Happening in an MRI?
1 2
3 4
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Water Molecules Random
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So they SpinWho Cares

• Rate of spin
• Amount of fat on the cells
• Myelin
• Lots of fat

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MRI Advantages and Limitations

• Advantages
• Amazing pictures of the brain!
• Limitations
• Very expensive
• Can not see brain activity
• Have to be very still
• Scary for kids (and adults!)

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MRI and fMRI Machine
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functional Magnetic Resonance Imaging
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Understanding fMRI

• Oxygenated blood sent to active areas.
• Active brain areas use oxygen.
• Results in deoxygenated blood.
• Deoxygenated blood polarized.

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What happens in fMRI
1 2
3 4
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So they SpinWho Cares

• Rate of spin
• Whether oxygenated or not

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Getting Pretty Pictures
High resolution scan
Low resolution scan
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Putting it Together
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Advantages and Limitation of fMRI

• Advantages
• Millimeter accuracy of where the activity is
  happening.
• Limitations
• Cant move during scanning
• Poor temporal accuracy
• Why poor temporal resolution?
• Remember EEG was great temporal accuracy

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fMRI in Developmental Research

• Very new (1995)
• The most difficult of all
• Youngest 7 years old

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Positron Emission Topography
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The Basic Idea

• Put tracer in body
• Tracer decays, emitting a positron.
• Positron hits an electron and explodes
• Shot out photons in opposite directions
• These are detected

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Graphic of What Happens
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Limitations and Advantages of PET

• Limitations
• Spatial limitations
• Traveling positron
• .4 1.4mm
• 8-15mm in practice
• Injection of tracer
• Decay of the tracer
• 2 minutes to 110 minutes
• Advantages
• Quick scan time (good for kids)

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Lecture Response

• Develop your own psychophysiological study!
• Language development
• Social development
• Auditory development
• Motor development
• Cognitive development
• Compare clinical and nonclinical groups
• Younger to older groups to see how things develop
• Comparison of tasks to see where things are
  handled in the brain