Chapter 5: The research methods of biopsychology

Question 1

What is x-ray photography?

Answer 1

a way of measuring internal structures through the way they absorb X-rays compared to their surroundings

Question 2

What are contrast x-ray techniques? What is a type of contrast x-ray technique commonly used?

Answer 2

Contrast x-ray techniques involve injecting a substance that absorb X-rays either less or more than its surroundings. Cerebral angiography is commonly used and it involves infusion of radio-opaque dye into the cerebral artery to visualize the cerebral circulatory system using x-rays.

Question 3

What is Computed tomography (CT)?

Answer 3

used to visualize the brain and other internal structures of the living body by collecting X-rays from a X-ray detector and creating 8 or 9 horizontal brain sections that can be combined into 3D form

Question 4

What is Magnetic Resonance Imaging (MRI)?

Answer 4

a procedure in which high resolution images are constructed from the measurement of waves that hydrogen atoms bit when they are activated by radio frequency waves in a magnetic field.
- Provides good spatial resolution (can see where things are located

Question 5

What is a Positron Emission Tomography (PET)?

Answer 5

• PET provides images of brain activity –> functional brain images rather than structural brain images
• involves injection of radioactive 2-DeoxyGlucose (2-DG into carotid artery
• 2DG is taken up by active cells and accumulates in the brain and those accumulations can be seen colour coated
• if you inject ligands into the brain (receptor fuel for a certain NT), you can see which NT’s are released in what part of the brain
• FLAW: it does not provide an overall picture of the brain (just bunch of colours)

Question 6

What is Functional MRI (fMRI)? What are two properties of oxygenated blood that can be measured?

Answer 6

• fMRI produces images of the brain that represent blood flow in the blood to the active areas of the brain
• Two properties of oxygenated blood:
  1. Active areas of the brain take up more oxygen
  2. oxygen has magnetic properties that can influence the radio-frequency waves emitted by H atoms in fMRI
• The signal recorded by fMRI is called a BOLD signal (blood-oxygen level dependent signal)

Question 7

What are 4 advantages that fMRI’s have over PETs?

Answer 7

1. Nothing has to be injected into the patient (non-invasive)
2. Provides both structural and functional information in the same image
3. its spatial resolution is better
4. Hydrogen can be used to produce 3D images of activity over the entire brain

Question 8

What is one disadvantage of fMRI?

Answer 8

it has poor temporal resolution (poor timing in terms of connecting the activity to the part of the brain)

Question 9

What is diffusion tensor Imaging? (DTI)

Answer 9

diffusion tensor imaging is a method of identifying pathways along which water molecules rapidly diffuse
- provides image of major tracts through rapid water diffusion in the brain

Question 10

What is transcranial magnetic stimulation (TMS)? What are 2 concerns regarding this method?

Answer 10

technique that can turn off an area of the cortex by creating a magnetic filed under a coil positioned next to the skull.

• 2 concerns:
  1. depth of effect
  2. mechanism of neural disruption

Question 11

What is snap electroencephalography? What are alpha waves?

Answer 11

When discs are placed on the scalp that record action potentials in electrical activity from skin, muscles, blood and eyes.
- Some are associated with states of consciousness like alpha waves which are 8-12 per second high amplitude waves that are associated with relaxed wakeful ness

Question 12

What are event related potentials (ERPs)? and what is a type of ERP?

Answer 12

Event related potentials are waves from EEG that accompany certain psychological events.
- one type is called sensory evoked potential and its the change in cortical EEG signal elicited by a momentary presentation of a sensory stimulus

Question 13

What are 2 properties of cortical EEG that follow a sensory stimulus?

Answer 13

1. Response to the stimulus (the signal)

2. The ongoing background EEG activity (the noise)

Question 14

What is signal averaging?

Answer 14

A method of reducing noise (background EEG) to get a higher signal:noise ratio.

Question 15

What is an average evoked potential (AEP)?

Answer 15

its a response to a stimulus that is recorded over a lot of trials and then averaged out

Question 16

What is the P300 wave in EEG? and what are far-field potentials

Answer 16

its the positive wave that occurs about 300 milliseconds after a momentary stimulus that has MEANING to a subject occurs.
- Far field potentials are portions of an evoked potential recorded in the first few milliseconds after a stimulus and its not influenced by meaning of stimulus

Question 17

What is magnetoencephalography?

Answer 17

measures changes in magnetic fields on the surface of the scalp that are produced by changes in underlying neural activity patterns

Question 18

What is a way of measuring muscle tension?

Answer 18

Electromyography results in electromyograms (EMG’s) between two electrodes taped to the surface of the skin over the muscle of interest.

• increase In muscle contraction = increase in amplitude of EMG signal recorded
• signals are processed as EMG spiking per unit of time

Question 19

What is a way of measuring eye movement?

Answer 19

Electrooculography records eye movement using a electrooculogram (EOG).

• placed above and below eye and one placed left and right of eye to record horizontal and vertical movements
• based on the steady potential differences between the front (positive) and back (negative) of the eye
• the steady potential causes a change in electrical potentials that are placed around the eye… the change in potential can be recorded

Question 20

What are two common indexes of electrodermal activity?

Answer 20

1. Skin conductance level (SCL) –> measure of the background level of skin conductance that is associated with a particular situation
2. Skin Conductance Response (SCR)
   - measures transient changes in skin conductance that are associated with discrete experiences

Question 21

What are the two parts of the cardiovascular system?

Answer 21

1. heart

2. blood vessels

Question 22

What are the 3 different measures of cardiovascular activity in psychophysiological research?

Answer 22

1. Heart rate –> using electrocardiogram (ECG)
2. Blood pressure –> using sphygmomanometer
3. Blood volume –> plethysmography (changes in the volume of particular parts of the body that are associated with physiological events)

Question 23

What are the three invasive techniques?

Answer 23

1. Lesion methods
2. Electrical stimulation methods
3. Invasive recording methods

Question 24

What is stereotaxic surgery? What are 2 parts used for stereotaxic surgery?

Answer 24

the means by which experimental devices are precisely positioned in the depths of the brain
the two things required are:
1. An atlas to provide directions to target site (stereotaxic atlas)
2. Stereotaxic instrument –> includes head holder and electrode holder

Question 25

What are lesion methods and what are 4 types of lesion methods?

Answer 25

1. Aspiration Lesions –> used when an area of cortical tissue is accessible to the eyes and instruments of the surgeon –> cortical tissue is drawn off by suction through a pipette
2. Radio Frequency Lesions –> lesions are made by passing radio-frequency current through the target tissue (burning it)
3. Knife cuts
   - cutting is used to eliminate conduction in an nerve tract
   - done by a sterotaxically positioned rod in the brain that has its blade swing out to make a small cut
4. Reversible lesions
   - temporary eliminates the activity of a particular area of the brain while tests are being conducted
   - done by cooling the area or by injecting anaesthetics like lidocaine

Question 26

What are 4 types of invasive electrophysiological recording methods?

Answer 26

1. Intracellular Unit Recording –> measures changes in the membrane potential over time. Involves a sharp micro electrode inside a single neutron
   - subject is fixed
2. Extracellular Unit Recording –> micro electrode is placed near outside of neuron and the signal is a series of spikes does not tell you about membrane potential just tells you about how much AP was fired
   - subject can move
3. Multiple-unit recording
   - uses a large tip to pick up signals from many neutrons and the AP’s are picked up by the electrode which uses an integrating circuit that adds them together
   - subject can move
4. Invasive EEG recording –> implantation of electrodes INSIDE the brain rather than on the scalp
   - Cortical EEG is recorded through skull steels and stereotypically implanted wire electrodes

Question 27

What are the 4 ways that drugs are administered in pharmacological experiments?

Answer 27

1. Fed to subject
2. intragastrically: injected through stomach
3. Intraperitoneally (intra means inside and peritoneal means the cavity of the abdomen) –> injected hypodermically (through the skin) into the peritoneal cavity of the abdomen
4. Subcutenously (sub means beneath and cutaneous means skin) –> into the fatty tissue beneath the skin
5. Intravenously –> into a vein

Question 28

How do they ensure that the drugs pass through the blood-brain barrier? what do they use to administer the drug into the brain?

Answer 28

1. they use a cannula which is implanted stereotaxically and its a tiny capsule that has drugs in it

Question 29

What is one way to make selective lesions using the pharmacological research method?

Answer 29

injecting neurotoxins in the brain via the cannula and then seeing which NT’s it affects therefore finding the areas that they are most active in and will get eaten up by the neurotoxin

Question 30

What are two important techniques for measuring chemical activity in the brain using pharmacological research methods?

Answer 30

1. 2-deoxyglucose technique –> slicing animals brain after injection with 2-DG and activity, and seeing what parts of brain took it up
2. Cerebral Dialysis –> used to measure extracellular concentration of specific neurochemicals in behaving animals. Drawing up liquid from ECF and then and then freezing it and preforming chromatography (measuring chemical components of it)

Question 31

What are two techniques of locating neurotransmitters and receptors in the brain?

Answer 31

1. immunocytochemistry –> uses to locate neuroproteins. the antibodies of the neuroprotein are dyed and regions accumulate in the brain to mark the location of the target neuroprotein (which also bind to NT of interest)
2. in-situ hybridization when an mRNA sequence is used to create the complementary strand of it with radioactive probes that bind to it (makes neuroproteins)

Question 32

What are three methods of Genetic engineering?

Answer 32

1. Gene knockout techniques –> procedure that creates an organism that lacks a gene to see how it functions
2. Gene replacement techniques –> when pathological (harmful) genes from human cells are inserted into other animals … creates transgenic animals
3. Green fluorescent protein (GFP) –> injecting a protein that exhibits bright light and having it get transferred to different areas of the brain via gene expression