CH 5: Research Methods of Biopsychology Flashcards

1
Q

Describe 2 x-ray based techniques for visualizing the living human brain.

A

(1) Contrast X-Ray Techniques:
- injecting into 1 compartment of the body a sub that absorbs X-rays less/more than surrounding tissues

(2) Computed Tomography (CT):
- computer-assisted x-ray procedures
- used to visualize brain & other internal organs

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2
Q

Describe the PET technique.

A
  • PET = position emission tomography
  • Visualizes brain activity via measuring the accumulation of radioactive flurodeoxyglucose (FDG) in active areas of brain
  • Each pet scan = image of levels of radioactivity (indicated by colour coding) in various parts of horizontal level of brain.

–> Used to show correlation b/w brain activity & cognitive activity, but can’t prove that brain activity CAUSED the cognitive activity

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3
Q

List 3 magnetic-field-based techniques for imaging the living human brain.

A
  1. MRI = magnetic resonance imaging
  2. fMRI = functional MRI
  3. Diffusion Tensor Imaging
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4
Q

Describe how an MRI is used to image the living human brain.

A
  • MRI = structural brain-imaging procedure
  • High-res images constructed from measurement of radio-frequency waves that H-atoms emit as they align w/ powerful magnetic field
  • Provides clearer images of brain than CT
  • Prod 3D images
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5
Q

Describe how an fMRI is used to image the living human brain

A
  • Prod images rep the ^O2 flow in blood to active areas of brain
  • Active areas of brain take up ^O2 blood
  • -> thus oxygenated blood accumulates in activate areas of brain
  • Oxygenated blood has magnetic properties that influence the radio-frequency waves emitted by H-atoms in MRI

–> Used to show correlation b/w brain activity & cognitive activity, but can’t prove that brain activity CAUSED the cognitive activity

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6
Q

Describe how DIFFUSION TENSOR IMAGING is used to image the living human brain

A
  • Identifies pathways along which H2O molecules rapidly diffuse
  • Helps understand connections among brain structures
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7
Q

List 2 trans-cranial stimulation techniques.

A
  1. Transcranial Magnetic Stimulation (TMS)

2. Transcranial Direct Current Stimulation (tDCS)

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8
Q

Describe TMS

A
  • MAGNETIC stim temp turns off part of brain while effects of disruption on cognition & behaviour are assess
  • Turns off an area of human cortex by creating a magnetic field under a coil positioned next to skull
  • Can also ‘turn on’ areas of cortex
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9
Q

Describe tDCS

A
  • ELECTRICAL stim temp ^activity in part of brain while effects of stimulation on cognition & behaviour are assessed
  • Stimulates (‘turns on’) area of cortex by applying an electrical current through 2 electrodes placed directly on scalp
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10
Q

What are trans-cranial stimulation techniques used to establish?

A
  • The causal effects of human cortical activity on cognition behaviour
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11
Q

List 2 psychophysiological measures of brain activity.

A
  1. Electroencephalography (EEG)

2. Magnetoencephalography (MEG)

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12
Q

Describe EEG.

A
  • Measure of gross electrical activity of the brain
  • Recorded via large electrodes placed on scalp
  • Scalp EEG signal reflects sum of electrical events throughout head – incl. action potentials & postsynaptic potentials etc.
  • Its value relies on fact that some EEG wave forms are ass w/ particular states of consciousness (ie. aroused, relaxed, asleep, etc)
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13
Q

Describe MEG.

A
  • Also monitors brain activity from scalp
  • Measures changes in magnetic fields on the surface of scalp that are produced by changes in underlying patterns of neural activity
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14
Q

List 2 psychophysiological measures of SOMATIC NS activity.

A
  1. Muscle tension

2. Eye movement

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15
Q

How is muscle tension psychophysiologically measured?

A
  • via Electromyography (EMG)

- EMG activity recorded b/w 2 electrodes taped to surface of skin over muscle of interest

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16
Q

How is eye movement psychophysiologically measured?

A
  • via Electrooculography (EOG)
  • based on fact that steady potential diff exists b/w the front (positive) & back (negative) of eyeball
  • When eye moves, a change in electrical potential b/w electrodes placed around eyes are recorded.
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17
Q

List 2 psychophysiological measures of AUTONOMIC NS activity.

A
  1. Skin conductance

2. Cardiovascular activity

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18
Q

How is skin conductance psychophysiologically measured?

Define SCL & SCR.

A
  • Emotional thoughts & experiences ass. w/ ^ability of skin to conduct electricity
  • Skin Conductance Level (SCL) = measure of background live of skin conductance ass. w/ particular situation
  • Skin Conductance Response (SCR) = measure of transient changes in skin conductance that are ass. w/ discrete experiences
  • -> ie) sweat glands become active in emotional situations
  • -> rel sweat
  • -> ^electrical conductivity of skin
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19
Q

How is cardiovascular activity psychophysiologically measured?

A

HEART RATE

  • Electrical signals ass. w/ each heartbeat recorded via electrodes placed on chest
  • Recording = ECG = electrocardiogram

BLOOD PRESSURE

BLOOD VOLUME

  • Changes in blood V in p articular parts of body ass w/ psychological events
  • ie) boner in men during sexual arousal
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20
Q

Define STEREOTAXIC SURGERY & list the 2 things it requires.

A

= Experimental devices precisely positioned in depths of brain

Requires:

  1. atlas to provide directions to target site
  2. instrument for getting there
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21
Q

List 4 types of lesion methods.

A
  1. Aspiration lesions
  2. Radio-frequency lesions
  3. Knife cuts
  4. Reversible lesions
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22
Q

Describe Aspiration Lesions

A
  • Aspiration = tissue drawn off by suction through fine tip of glass pipette
  • Used when lesion is made in area of cortical tissue that’s accessible to the eyes & instruments of surgeon
  • -> Leaves underlying white matter & major bv’s undamaged
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23
Q

Describe Radio-Frequency Lesions

A
  • Pass radio-frequency current through target tissue to destroy tissue
  • Intensity & duration of current depends on size of tissue
24
Q

Describe Knife Cuts

A
  • Sectioning (cutting)

- -> Eliminates conduction in a nerve or tract

25
Q

Describe Reversible Lesions

A
  • Temp eliminate the activity in particular part of brain while tests are conducted
  • Advantage = same subjects can be repeatedly tested in both lesion & control conditions
26
Q

Explain why it’s important to be cautious when interpreting the effects of lesions (2).

A
  1. Brain structures are small & tightly packed
    - -> Can’t completely destroy a structure w/o prod sig damage to adjacent structures
  2. Behavioural effects of unilateral lesions (lesions on 1/2 of brain) are much milder than symmetrical bilateral lesions
27
Q

Describe the technique of ELECTRICAL BRAIN STIMULATION.

A
  • Electrically stimulating neural structure –> give clues about its function
  • Important bc often has behavioural effects
  • is INVASIVE procedure, often tested on nonhumans
28
Q

List 4 invasive electrophysiological recording methods.

A
  1. Intracellular unit recording
  2. Extracellular unit recording
  3. Multiple-unit recording
  4. Invasive EEG recording
29
Q

Describe Intracellular Unit Recording

A
  • Provides moment-by-moment record of graded fluctuations in one’s neuron’s membrane potential
30
Q

Describe Extracellular Unit Recording

A
  • Record action potentials of neuron through micro electrode tip placed in extracellular fluid next to it
  • Provides record of firing of a neuron but NO info about the neuron’s membrane potential
31
Q

Describe Multiple-Unit Recording

A
  • ^Larger electrode tip - picks up signal from many neurons

- Slight shift in movement of subject have minimal effect on overall signal (unlike above)

32
Q

Describe Invasive EEG Recording

A
  • EEG signals recorded through large implanted electrodes rather than scalp electrodes
33
Q

Describe the 3 methods of drug administration.

A
  1. Fed to subject
  2. Injected through tube into stomach
  3. Injected hypodermically into:
    - peritoneal cavity of abdomen
    - large muscle
    - fatty tissue beneath skin
    - large surface vein
  • -> problem w/ peripheral routes of admin = drugs don’t readily pass through blood-brain barrier
  • -> admin drugs in small amounts through fine tube stereotaxically implanted in brain
34
Q

Define NEUROTOXINS

A
  • Neural poisoning = affinity for certain components of NS
35
Q

Describe the method of selective neurotoxic lesions.

A
  • Neurotoxins injected to make more selective lesions
  • Bc effects of surgical, radio-frequency & reversible lesions are hard to interpret bc they affect all neurons in area.
36
Q

List 2 techniques for measuring chemical activity in the brain.

A
  1. 2-Deoxyglucose Technique

2. Cerebral Dialysis

37
Q

Describe how 2-Deoxyglucose Technique is used for measuring chemical activity in the brain.

A
  • Place animal that’s been injected w/ radiative 2-DG in test situation where it engages in activity of interest
  • 2-DG is similar to glucose (brain’s main source of E)
  • -> neurons active during test absorb 2-DG but don’t metabolize it
  • Kill subject, remove & slip brain, analyze parts of brain that absorbed high levels of radioactive 2-DG
38
Q

Describe how Cerebral Dialysis is used for measuring chemical activity in the brain

A
  • Measures extracellular [ ] of specific neuro-chemicals in behaving animals
  • Implantation in brain of fine tube w/ short semipermeable section
  • -> Positioned in brain structure of interest so that extracellular chem of structure diffused into tube
  • Collect contents of tube to freeze, store & later analyze
39
Q

List 2 techniques for locating particular NTs or receptors in brain.

A
  1. Immunocytochemistry

2. In Situ Hybridization

40
Q

Describe how Immunocytochemistry is used for locating particular NTs or receptors in the brain.

A
  • Locates particular neuro-proteins in brain by labelling their antibodies w/ dye or radioactive element
  • -> Then expose slices of brain tissue to the labelled antibodies
  • Regions of dye radioactivity accumulation in brain slices mark the locations of target neuroprotein
  • Expose brain slices to labelled antibodies that bind to enzymes located in only those neurons that contain the NT of interest
41
Q

Describe how In Situ Hybridization is used for locating particular NTs or receptors in the brain.

A
  • Locates peptides & other proteins in brain
  • Identify nucleotide base sequences that direct stn of many neuroproteins
  • -> artificially create the complementary base sequences
  • see pg 117 for details
42
Q

Describe Gene Knockout Techniques

A
  • Creating organisms that lack a particular gene
  • Conducted to clarify the neural mech of behaviour
  • Behaviour is controlled by many genes interacting w/ another + experience via epigenetic mech
43
Q

Describe Gene Replacement Techniques

A
  • Creating organisms where a particular gene is replaced w/ another
44
Q

Define TRANSGENIC

A
  • ie) transgenic mice = contains genetic material of another sp
45
Q

Explain how green fluorescent protein has been used as a research tool in neurosciences.

A
  • GFP = Green Fluorescent Protein = pro that exhibit bright green fluorescence when exposed to blue light
  • Strategy: Insert GFP in target cell
  • -> Activate GFP gene in only the particular cells under investigation
  • -> ^visualization
46
Q

Define OPSINS

A
  • Light-sensitive ion channels found in cell membranes of certain bacteria & algae
47
Q

Explain how opsin have been used as a research tool in the neurosciences

A
  • Opens & allows ions to enter cell when illuminated w/ light
  • Light can either hyper polarize or depolarize the cell membrane
  • Insert opsin gene into particular types of neurons
  • Activate opsin channels
  • -> ^ or suppress activity of neuron
48
Q

List 3 approaches to neuropsychological testing

A
  1. Single-Test Approach
  2. Standardized-Test-Battery Approach
  3. Customized-Test-Battery Approach
49
Q

Describe the Single-Test Approach. Is is successful or unsuccessful?

A
  • Goal = discriminate b/w patients w/ psych problems resulting from structural brain damage, vs. those w/ psych problems resulting from functional (rather than structural) changes to brain
  • UNSUCCESSFUL approach bc no single test can be sensitive to the varied & complex psych symptoms occurring in brain-danged patient
50
Q

Describe the Standardized-Test-Battery Approach.

Pros & cons?

A
  • Identify brain-damaged patients using standardized batteries (sets) of tests rather than a single test
  • Add together test scores to form single aggregate score
  • -> If below designated cutoff, then brain damage diagnosis
  • Good at discriminating b/w neurological patients & healthy ppl
  • NOT good at discriminating b/w neurological patients & psychiatric patients
51
Q

Describe the Customized-Test-Battery Approach

A
  • Objective = characterize nature of psych deficits of each brain-damaged patient
  • Starts w/ common battery tests to provide indication of general nature of neuropsychological symptoms
  • Dependent on test results, select series of tests customized to each patient to characterize more detail of the symptoms revealed by common batter
  • see pg 121-122 for more details
52
Q

Describe the 4 types of tests that are often administered as part of an initial common neuropsychological test battery.

A
  1. INTELLIGENCE
    - Knowing a patient’s IQ can help a neuropsychologist interpret the results of subsequent tests
  2. MEMORY
    - Limitation = 2 forms of memory are least likely to be disrupted by brain damage
  3. LANGUAGE
  4. LANGUAGE LATERALIZATION
    - Knowing which hemisphere is dominant for language is useful in interpreting results of other tests
  • see pg 123 for more details
53
Q

Describe the WISCONSIN CARD SORTING TEST

A
  • **Evaluates patient’s ability to remember that previously learned rules of behaviour are no longer effect & to learn to respond to new rules
  • Sort cards based on diff rules each time (ie. by colour, shape, etc.)
  • Patients w/ damage to frontal lobes cont. to sort on basis of 1 sorting principle
  • Difficulty learning & remembering that previously appropriate guidelines for effective behaviour are no longer appropriate
54
Q

Describe the PAIRED-IMAGE SUBTRACTION TECHNIQUE

A
  • Use of PET of fMRI to locate constituent cognitive processes in brain by prod an image of the diff in brain activity ass w/ 2 cognitive tests that differ WRT a single constituent cognitive process
  • Involves obtaining functional brain images during several diff cognitive tasks
  • Brain activity ass w/ that process estimated by subtracting the activity in the image ass w/ one of the 2 tasks from the activity in the image ass w/ the other
  • see pg 125 for more details
55
Q

Define DEFAULT MODE

A
  • Pattern of brain activity present when person sits quietly & lets their mind wander
56
Q

Define DEFAULT MODE NETWORK & the structures that are a part of it (4)

A
  • Network of brain structures active when brain in default mode
  • Comprised of many structures incl. 4 cortical areas:
    1. Medial parental cortex
    2. Lateral parental cortex
    3. Medial prefrontal cortex
    4. Lateral temporal cortex
57
Q

Explain what a MEAN DIFFERENCE IMAGE is.

A
  • Mean = averaged
  • DIFFERENCE IMAGE = In context of functional neuro-imaging, the average of the difference images (obtained via paired-image subtraction) obtained from multiple participants
  • Averaging can lead to a problem:
  • -> If 2 ppl had specific but diff patterns of cortical activity, the average image derived would reveal little about either