5. Research Methods

Question 1

golgi stain

Answer 1

golgi stain is taken up by few neurons

Shows outside neuronal structure in great detail

Question 2

Nissl stain

Answer 2

provides gross indication of brain structure by selectively staining groups of neural cell (low magnification)

individual neural cell bodies can be distinguished a high resolution

Question 3

what are the comparisons between the nissl and golgi stain?

Answer 3

• Golgi stain shows shape and reach of neurons.

* Nissle stain shows number of neurons in each layer.

Question 4

what different layers of the neicortex do nissl and golgi stains reveal?

Answer 4

1. molecular layer
2. External granular layer
3. external pyramidal layer
4. internal granular layer
5. internal pyramid layer
6. multiform layer

Question 5

electron microscope

Answer 5

• Preparation of tissue slices with electron-absorbing substance
• Neuronal structure captured in great detail.

Question 6

what are contrast x eays?

Answer 6

used for visualising the living brain. they are an adaptation of standard X-ray technique

Question 7

how do contrast x-rays work?

Answer 7

• Inject radiopaque substance into structure of interest
• Radiopaque substance absorbs X-rays
• Result: increased contrast with neighbouring tissue
• Specific technique: Angiography

Question 8

what do Computed (axial) Tomography do?

Answer 8

• CT scan provides 3D view of brain structure

* Image not sharp

Question 9

how do CAT work?

Answer 9

• X-ray gun & X-ray detector rotate appositionally at about 8 different levels of the brain
• Image constructed from combined scans
• Figure shows CT scan of one level
• Each pixel (picture element) results from complex mathematical computation of associated brain region viewed from different angles
• Spatial resolution high enough to observe even small changes (e.g., shrinkage of a gyrus)

Question 10

Where are CATs used?

Answer 10

Used in a number of disorders (e.g. Alzheimer’s, dyslexia)

Question 11

Magnetic Resonance Imaging

Answer 11

MRI has greater contrast resolution than CT; no exposure to X-rays
• Provides 2D and 3D images
• Resolution superior: neural structures vary in hydrogen atom density
• Reveals very small changes, such as loss of myelin around groups of axons

Question 12

How do MIRs work?

Answer 12

Measures waves emitted by hydrogen atoms when placed in magnetic field
Provides 2D and 3D images

Question 13

What do Positron Emission tomographys do?

Answer 13

Highlights active brain regions (rather than showing all)
• Brain can be mapped during different states (attention, movement, tasks)
• Can identify also abnormally functioning regions

Question 14

how do the Positron Emission tomographys work?

Answer 14

• Injection of radioisotopes (e.g. , 2-deoxyglucose): differential uptake
• 2-DG (type of radioactive glucose) taken up but cannot be metabolised
• Increased metabolic activity revealed through accumulated radio-activity

Question 15

What do Functional MRI (fMRI) do?

Answer 15

Can detect oxygen consumption in active brain regions

• BOLD signal (blood-oxygen-level-dependent signal)

Question 16

how do fMRIs work?

Answer 16

• Improvement on MRI in terms of speed (temporal resolution)

* Uses rapidly oscillating magnetic field gradients & more powerful computational techniques

Question 17

What is the benefits between fMRI and PET?

Answer 17

• No substances injected
• One image provides structural and functional information
• Better spatial resolution
• Real time measurements; can measure many times from same person

Question 18

what are the difficulties with the fMRI and PET

Answer 18

• Noise

* Disentangling various cognitive processes

Question 19

What does Transcranial Magnetic Stimulation do?

Answer 19

Stimulates the living brain
• NOT a measure of neural activity
• Provides an experimental probe to alter neural activity

Question 20

how do Transcranial Magnetic Stimulations work?

Answer 20

TMS applies a brief, strong magnetic field that alters neural activity
• Can either activate or “deactivate” brain structures
• Observe changes in behavior in consequence to manipulation

Question 21

what does Electroencephalography do?

Answer 21

records physiological signals.
• EEG represents sum of all electrical activity: does not reveal underlying
neural activity
• EEG wave forms associated with different states of consciousness

Question 22

EEG signal

Answer 22

difference as a function of time in electrical potential between two scalp electrodes

Question 23

what is seen in epileptic seizures according to the EEG?

Answer 23

synchronised depolarisation of neurons.

Question 24

What does Event-related potentials (EPRs) record?

Answer 24

physiological signals.

They reveal characteristic peaks (with differing latencies and amplitudes)

Question 25

How do Event-related potentials work?

Answer 25

Filtered electrical activity (obtained from scalp EEG) associated with specific cognitive processes. The ERP signal is obtained through signal averaging. The resulting ERP reveals characteristic peaks (with differing latencies and amplitudes)

Question 26

what is the advantage of Event-related potentials?

Answer 26

real time measurement

Question 27

what does stereotaxic atlas show?

Answer 27

the position of the target location e.g. the atlas indicates that the amygdala target site is 2.5mm posterior to bregma. 4.5mm laterla and 8.5mm vertical

Question 28

Bregma

Answer 28

where the skill fuses is reference point

Question 29

stereotaxic unstruments

Answer 29

head holder and electrode holder

Question 30

what is the process of stereptaxic surgery performed on mice?

Answer 30

1. the atlas indicates that the amygdala target site is 2.8mm posterior to bregma. 4.5mm lateral and 8.5mm vertical 2. A hole is drilled 2.8mm posterior to bregma and 4.5mm lateral to it. Then, the electrode holder is positioned over the hold and the electrode is lowered 8.5mm through the hole 3. The electrode is anchored to the skill with several stainless steel screws and dental acrylic that is allowed to harden around the electrode connector

Question 31

what are the kinds of lesion methods?

Answer 31

aspiration method radio-freqency lesions sectioning cryogenic blockade

Question 32

aspiration method

Answer 32

visible part of cortical regions; tissue drawn off by suction

Question 33

radio-frequency lesions

Answer 33

currents of radiofrequency through stereotaxic isntrument -> heat destroys target region

Question 34

sectioning

Answer 34

(Subcortical knife cuts) | Eliminates nerve or tact conduction

Question 35

crygenic blockade

Answer 35

reversible lesion. Temporarily eliminates activity in target area. Same subject an be case and control

Question 36

Electrical stimulation

Answer 36

effect usually opposite to that of lesion. Done prior to lesioning

Question 37

What are recording methods?

Answer 37

intracellular recording extracellular unit recording multiple unit recording invasive EEG recording

Question 38

what is the process of intracellular recording?

Answer 38

Electrode enters neuron through amplifier.

Question 39

Intracellular unit recording

Answer 39

an intracellular microelectrode records the membrane potential from one neuron as it fires

Question 40

An extracellular unit recording

Answer 40

An extracellular micro-electrode records the electrical disturbance that is created each time an adjacent neuron fires

Question 41

A multiple-unit recording

Answer 41

A small electrode records the action potentials of many nearby neurons. These are added up and plotted.

Question 42

An invasive EEG recording

Answer 42

A large implanted electrode picks up general changes in electrical brain activity. The EEF signal is not related to neural firing in any obvious way

Question 43

what are the pharmalogical methods?

Answer 43

drug administration selective chemical lesions measuging chemical activity in behavioural studies Locating neurotransmitters and receptors in the brain

Question 44

drug administration focuses on...

Answer 44

the effect of neurotransmitters

Question 45

what are the common methods of drug administration?

Answer 45

intragastric, intraperitoneal, intramuscular, suhcutaneous --> difficulty of traversing blood-brain barrier

Question 46

intraventricular cannula

Answer 46

drug administration method where a small tube is implanted in the brain

Question 47

selective chemical lesions

Answer 47

injection of neurotoxins

Question 48

What are the techniwues chemical activity in behavioural studies?

Answer 48

* 2-deoxyglucose technique | * In vivo cerebral microdialysis

Question 49

What is involved in locating neurotransmitters and receptors in the brain?

Answer 49

immunocytochemistry | In-situ hybridisation

Question 50

immunocytochemistry

Answer 50

antobody generation for neuropeptides

Question 51

In-situ hybridisation

Answer 51

Acts on messenger RNA

Question 52

What are the techniques involved in genetic engineering?

Answer 52

Gene knock-out techniques | Gene replacement techniwues

Question 53

gene knock-out technique

Answer 53

lack of specific gene

Question 54

Gene replacement technique

Answer 54

replace one gene with another

Question 55

what is an example of the gene replacement techniques?

Answer 55

* transgenic mice (receive genetic information from different species * modified genes inserted to switch on/off gene at different developmental periods

Question 56

neuropsychological testing

Answer 56

* Information obtained assist in diagnosis of specific disorder * Evaluation of treatments (before & after) * Rehabilitation * Insight into cognitive functioning * Behavioural effects of lesions

Question 57

what are the common neurpsychological tests?

Answer 57

``` Single-test vs batter approaches • Intelligence (e.g. WAIS) • Memory • Language • Language lateralisation • Frontal lobe function ```

Question 58

what is an example of a language lateralisation test?

Answer 58

Sodium amytal, dichotic listening

Question 59

what is an example of frontal lobe functioning test?

Answer 59

Wisconsin Card Sorting Test

Question 60

what are some behavioural paradigms in the lab?

Answer 60

* Species common behaviours * Traditional conditioning paradigms * Learning paradigms

Question 61

what are the traditional conditioning paradigms?

Answer 61

* Pavlovian paradigm | * Operant conditioning

Question 62

what are some learning paradigms?

Answer 62

* Taste aversion * Radial arm maze * Morris water maze * Defensive burying