Methods Flashcards
1
Q
Invasive methods
A
-associated introducing instruments into the body
2
Q
Experimental ablation
A
- invasive
- lesioning
- removal or damage to part of the brain
- may be permanent or temporary
- same animal can be used as a control (contralateral side)
3
Q
Lesions
A
- invasive
- radio frequency lesion (permanent) that destroys tissue around electrode
- also applied in therapy for human patient treatment
- neurotoxic lesion (mostly permanent) using toxins that destroy neurons
- infusion of anesthetic, muscimol, or local cooling
- reversible approaches
4
Q
Local stimulation/recording of neuronal activity
A
5
Q
Microdialysis
A
- use semipermeable membrane to deliver substance or collect released substance from neurons
- cons: low temporal resolution
- fast-scan cyclic voltammetry as a substitution with better resolution but it is difficult to do
6
Q
Microiontophoresis
A
-allows to inject minute amounts of a substance and measure its effect on a neuron
7
Q
EEG
A
- measures electrical ectivity in the brain using electrodes attached to the skull
- one of oldest methods
- pros: cheap, safe, well-developed
- cons: low spatial resolution
- sleep studies rely on EEGs
- lie detectors
- measuring IQ
8
Q
MEG
A
- measures magnetic changes generated by neuronal activity
- pros: high spatial resolution
- cons: expensive and requires sophisticated methods to eliminate environmental magnetic interference
- low harm
9
Q
iEEG
A
- intercranial EEG
- invasive
- better spatial resolution but could damage tissue
- used in situations for epilepsy
10
Q
In vivo imaging - computerized axial tomography
A
- computerized (axial) tomography
- non insvasive
- uses X-ray beam to show brain structure
- often combined with other imaging (PET) to enhance structure recognition
11
Q
MRI
A
- in vivo imagining
- atomic nuclei emit energy in magnetic field
- now evolved into MRI, fMRI, and MRS
- shows structure and function
12
Q
PET
A
- positron emission tomography
- in vivo imaging
- positron + electron = gamma waves
- requires the cyclotron to produce the positron matter
- 18F most commonly used (expensive)
-SPECT: uses gamma emitting isotopes, cheaper than PET, often combined with CT
13
Q
Transcranial magnetic stimulation
A
- non invasive
- stimulate brain regions using magnetic fields
- repeated application of TMS pulses at regular intervals is called repetitive TMS
- used for patient treatment
- can be used to treat pain, depression, OCD, schizophrenia, PTSD, panic disorder, Parkinson’s
- doesnt have great precision
14
Q
Deep brain stimulation
A
- invasive
- stimulate brain regions using electric impulses and creating local field potentials
- electrodes implanted using stereotactic surgery
- useful in treatment of movement disorders
- dystonia, tremor, pain, Huntington’s
- depression, addiction, dementia, MS, stroke, TBI, Tourette etc
- many risks
- patients must have electrodes continuously to benefit from treatment
15
Q
Face validity
A
-the degree to which a procedure appears effective in terms of its aims stated
16
Q
Empirical/construct validity
A
-the degree to which a test measures what it claims to measure
17
Q
Open field test
A
- used as prelim test to evaluate locomotor activity
- smells must be eliminated if using same cage for multiple species
- quantitative
- infrared beams, video tracking, distance moved, velocity (reliable)
- qualitative
- rating scales, tallies of exploratory behaviour, grooming (less reliably
18
Q
Locomotor function and balance
A
- beam walk test
- measures time to cross, distance before falling, number of stops, number of slips
- difficulty may be increased by reducing rod diameter
- RotaRod
- mice placed on rotating rod
- latency to fall is measured
- tests motor learning, balance, coordination, muscle strength, fitness
19
Q
Animal behaviour tests - pain
A
- Tail flick test
- beam of light focused on tail latency to remove tail is measured
- Hot plate test
- animal placed on heated surface
- latency to kick back paws/ escape measured
- tested animals should be same age due to skin thickness
- most also test cold plate
- Formalin test
- dilute injection to assess pain behaviour
- can cause chronic pain
- 2 waves: instant and delayed pain
20
Q
Learning and memory - mazes
A
- can be simple T-maze or Y maze
- study exploratory behaviour
- cheap and easy
- sometimes animal must be food/water deprived to motivate behaviour
- can be used for different species
- may be useful for evaluation of other measures (photaxis)
-impaired vision could affect data
21
Q
Radial arm maze
A
-designed to measure spatial learning and memory
- advantage
- utilizes animals normal foraging behaviour
- disadvantage
- food deprivation
- difficult to eliminate scent tracks
- takes up a lot of space
22
Q
Morris water maze
A
- popular to study spatial learning and memory
- size of platform and tank may vary
- water is opaque
- advantages
- no scent cues
- no food deprivation
- disadvantages
- swimming is stressful
- must be able to see (hard to tell if rodent has good vision)
- hippocampus lesions produce difficultly in learning
- improved if subsequent trails start at same point
- no learning if start location changes
23
Q
Barnes maze
A
- developed by Dr Carol Barnes
- round platform with holes
- one hole has escape
- advantages
- less stressful
- no food deprivation
- disadvantages
- scent cues
- lower motivation
24
Q
Passive avoidance
A
- fear learning
- animal placed in brightly lit compartment
- entering dark compartment associated with a foot shock
- latency to enter dark compartment is a measure of memory
- scopolamine used to impair memory for this task
- cholinergic receptor antagonist
25
Novel object recognition test
- based on natural tendency of rodents to spend more time exploring novel objects
- choice to explore novel object reflects the use of learning and recognition memory
- animal first familiarized with 2 objects
- one then replaced by another similar object
- memory evaluated by latency to explore novel object
- advantages
- non-forced
- non-invasive
26
Elevated plus maze
- test of anxiety
- based on conflict between staying safe and exploring new, unsafe environment
- anxiolytics increase time spent in open arms
-MK-108 (NMDA glutametergic anatagonist)
27
Depressive behaviour
-3 commonly used behavioural tests
1. Learned helplessness
- inescapable then escapable shock
2. Forced swim test
- coping behaviours: swimming, struggling
- learned helplessness: immobility
3. Sucrose preference test
- models anhedonic aspect of depression
28
Porsolt forced swimming test
- depression like phenotype is associated with lower latency to stay immobile and less swimming/efforts to escape beaker
- antidepressants have opposite effects
- increase latency and extend swimming time
- usually a short test (6 min)
- easy and cheap method
-cruel
29
Tail suspension test
- considered to be better choice than porsolt test
- depressive behaviour associated with reduced latency in upright position
- advantages
- no water immersion
- doesnt require sophisticated equipment
- disadvantages
- very cruel
- some strains use their tail to climb
30
Marble burying test
- 2 marbles evenly distributed on surface
- 30 min time
- burying is natural behaviour for mice
- those which bury more marbles in same time express repetitive behaviour
- model for autism
- also used to test anxiety and OCD
- validity is controversial
31
Measuring addictive behaviour
- using one bottle or two bottle paradigm to study alcohol drinking
- more complex methods use principle of classical (conditioned place preference) or operant (drug self-administration) conditioning
32
Conditioned place preference
- based on classical conditioning
- uses 2 distance environments
- 1 paired with drug
- 1 pairs with vehicle
- advantages
- reflects motivational state
- relatively easy
- animals tested in non-drugged state
- can determine preference and aversion
- disadvantages
- injections are adversity
- animals innate preferences
- non-contingent drug administration
33
Self administration
- based on operant conditioning
- operant response (lever press/ nose poke) results in IV administration of drug or direct delivery to brain
- advantages
- high face validity and contingent drug administration
- control over drug dose and timing
- can use progressive ration to determine motivational breaking point
- can determine reinforcing properties of drug and rewarding properties of secondary reinforcers
34
Behavioural methods for humans
- need to obtain consent and approval of ethical committee is more difficult
- usually the demeaned characteristic is high (deception needed)
- common use of self reporters (bias)
35
Pain testing in humans
1. Face scale: o ring ally developed for evaluating pain in children
2. Cold pressor test
3. McGill pain questionnaire
-sensory, affective, evaluative descriptors of pain
3 measures: pain rating index, number of words chosen, present pain intensity
36
Cold pressor test
- hand immersed in ice bath
- threshold and tolerance measured
- HR and BP measured
- in healthy subject the procedure increases BP and HR
- more painful variant uses heat bath immersion
-method useful for a valuations cardiac response also
37
Cold pressor test study
- 60 healthy undergrad participants
- results
- describing painkiller produces significantly less pain in second trial and increases tolerance
-authors suggest that this kind of unconscious priming may have clinical application
