Use of animals in research Charlotte Bonardi. Issues Why are animals used in Psychology? How? What...

Use of animals in research

Charlotte Bonardi

Issues

Why are animals used in Psychology?

How?

What are the benefits?

Ethical issues: what are the safeguards?

Who uses animals?

Biology: study of animals for their own sake

Cognitive psychology: study of common cognitive processes

Comparative psychology: compare cognitive skills in animals

Neuropsychology – which bits of the brain are involved?

Medical psychology: animal models of mental illness

Who uses animals?

many involve the study of learning (i.e. memory) in animals...

but how can you do this?

and why even think of using animals in the first place?

Issues:

whether you can study learning in animals depends on:

- what you think learning is

- whether we all learn in the same way

Philosophical position on this has changed over time

learning a rule-based mental process - information encoded

can't see inside the mind..

but can see information

input

learning a rule-based mental process - information encoded

can't see inside the mind..

but can see information

input

..and a predictable change in behaviour results -- output

animals probably do something similar, maybe less well...

but this is a modern view.....

relatively recently (1500’s) people used to think of even non-living things animistically – with desires and so on -- in the same way as humans

e.g. magnets

attraction/repulsion

“moving together in voluntary union”

....superseded by mechanistic view

Descartes (1596 - 1650) - dualist:

distinguished mind and body. Man

has mind which interacts with

body in pineal gland.

because he is sceptical about the

external world, much knowledge comes

from deduction not perception...

i.e. learning unobservable

Animals explicable in terms of physical principles – robots

Locke (1632-1704) All ideas originate in

experience. Idea is unit of mind, simple

ones make up complex ideas

association of ideas - a learning rule

Hume (1711-1776) - distinguish impressions

(sensations) and ideas (experienced in

absence of object).

Laws of association: resemblance,

contiguity, cause and effect (correlation).

Psychological processes are analysable;

learning comes from experience -- input is observable

James Mill (1773-1836)

refined the idea of the association of ideas,

that mirror sensations that we experience

Empiricist/Associationist approach forms basis of psychology as an experimentally tractable subject

Can study mind by relating external stimuli (input) to psychological output (e.g. report, or other behaviour)

Introspectionism mainly Germans e.g. Fechner, Weber, Wundt

Fechner (1801-1887) pioneered psychophysics - study of sensations evoked by physical stimuli - using techniques like measuring just noticeable differences and relating them to physical stimulus magnitude

Würzburg School - highly trained observers used for psychological experimentation

used introspection and

report as measure

..which rules out use of

animals...

Behaviourism: Reaction to introspection: data must be publically observable and so independently verifiable.

relate external stimuli to behaviour, not psychological report.

obvious? maybe not...

e.g work on stereotyping - get different results from self report and affective priming measures...

"I love Norwegians!" but

Norwegian - happy slower than Norwegian - dreadful

Darwin (1809-1882) - theory of evolution,

implies continuity between man and

animals

So theoretically in a position to

study animals...

study of learning involves looking at information input and measuring behaviour output

and rats and man are on a continuum

but what of the theories?

Radical Behaviourists

Only deal with S and R - no unobservable mental events

e.g. Skinner (1904-1990) attempted a complete account of behaviour - response either elicited by a stimulus or controlled by a consequence...

but....

what is a response? If rats learn a maze, and then it is flooded, do they try and walk? If it's S-->R they should.....!

Tolman (1886-1959) better to think of responses at molar level e.g. approach end of maze, not reflexes involved in walking

Radical Behaviourists

SR can’t do goal-directed behaviour:

many of these theories see reinforcement as a glue cementing SR relationship

cat in puzzlebox (Thorndike) – makes lots of responses until one allows it to escape. Frequency of this response increases because it has been rewarded. BUT

Leverfood then food illness

strict SR says you should keep on pressing the lever

Cognitive Behaviourists

cumbersome: e.g. cat in front of barking dog... arches back, hisses, hair on end, etc...

cat-->R1 cat-->R2 cat-->R3 cat-->R4 etc...

instead:

e.g. cat in front of barking dog... --> fear --> arches back, hisses, hair on end etc

fear is an intervening variable: not directly observable, but useful if strongly tied to observable events - what causes it and what effect it has. And can be linked to internal states sometimes e.g. adrenaline

eating dry food runs maze for

water

deprive of water drinks water

inject with saline presses lever for water

eating dry food runs maze for

water

deprive of water thirst drinks water

inject with saline presses lever for water

From Hall 1983

Modern Cognitive Behaviourism

mental representations activated by presentation of environmental events

associations form between representations of two events that are reliably paired, so presenting one will activate the other....

tone food response food

tone

Modern Cognitive Behaviourism

Associative learning allows us to learn causal relationships in our environment - found in all vertebrates - very general mechanism

explains much learning in animals – and also people

e.g. connectionist networks - explain complex human cognitive skills in terms of associations

Cognitive Psychology

So modern theories of animal learning will work for humans too..

But why still bother?!! why not cut to the chase and test humans?

Because...

Huge existing research base on associative learning in animals

and associative theory is the most comprehensive theory of learning we have...

Very high levels of experimental control possible:

prior experience - e.g. stimulus novelty

current experience - stability of conditions

motivational control

Interference of higher level processes

experimenter demands

higher level reasoning

prior knowledge

context effects

So this is why we study animals for cognitive psychology...

for comparative psychology it’s obvious

how about neuropsychology?

Neuropsychology: aim is to understand how the brain works - how it produces psychological phenomena

can't we study the behaviour of the organism without knowing how it is produced?

data can aid theoretical development - if theory says skills a and b depend on the same process, but lesion affects only skill a, theory wrong....

understanding underlying systems can help deal with pathology

parallels can lend credence to theory - e.g. associations and neurons

Issues with studying neuropsychology in animals

assumes homology of anatomy, if knowledge is to apply to man

assumes mapping of psychological/behavioural phenomena - cf. hippocampus

Advantages - Techniques available!

compared to techniques available in humans, where until recently only had patients with brain damage - uncontrolled, no idea what they were like before, etc

more modern imaging techniques vary in definition, scope etc

e.g. fmri: supposedly measures neural activity while doing a task

- but actually measures oxygenation of blood

– indirect measure of neural activity

and which neurons? excitatory? inhibitory?

which neurotransmitter system? etc etc...

Advantages - Techniques available!

techniques available now in humans very important – but not perfect

the range of different techniques available in animals offer powerful complementary strategies to understand how the brain works

Lesions - selective anatomically, and in neurotransmitters targeted

lesion cell bodies leaving fibres of passage intact - e.g. ibotenic acid, NMDA

can target specific neurotransmitter systems - e.g cholinergic denervation by e.g. 192IgG-saporin (SAP)

Lesions - selective anatomically, and in neurotransmitters targeted

lesion cell bodies leaving fibres of passage intact - e.g. ibotenic acid, NMDA

can target specific neurotransmitter systems - e.g cholinergic denervation by e.g. 192IgG-saporin (SAP)

disconnection lesions - destroy half of two structures, thus destroying communication between them, but leaving them functioning independently. If function depends on interaction, it will be impaired

Disconnection of the anterior cingulate cortex and nucleus accumbens core impairs Pavlovian approach behaviour (Parkinson et al., 2000)

Lesions -- limitations

lack of precision -- collateral damage

confounding behavioural effects – e.g. activity

limitations of histological assessment – where is it?

Neurotransmitters and drugs -- cannulate specific agonists or antagonists into specific brain areas

Double dissociation of the behavioural effects of R(+) 7–OH–DPAT infusions in the central and basolateral amygdala nuclei upon Pavlovian and instrumental conditioned appetitive behaviours (Hitchcott & Phillips, 1998)

can investigate the degree to which these effects are influenced by other drugs in other areas

Effects of intra-amygdala R(+) 7-OH-DPAT on intra-accumbens d-

amphetamine-associated learning (Hitchcott & Phillips, 1998)

Neurotransmitters and drugs - limitations

problems with spread of neurotransmitters

do you need control infusions in other areas that don't show the effects?

confounding behavioural effects again

Transgenics -- strains of mice have been developed in which

genes are modified - knockout and knockin

MANY types; e.g. Tg 2576 develops plaques similar to those

seen in Alzheimer's disease

Transgenic animals are frequently created by either microinjection of DNA sequences into the chromosomes of fertilized eggs, or genome is modified in embryonic stem cells, and then inject into embryo, where they are assimilated. Latter technique allows addition as well as removal of sequences.

Zhuo et al., (2007) Early discrimination reversal learning impairment and preserved spatial learning in a longitudinal study of Tg2576 APPsw mice.

Transgenics - limitations

some of these gene replacement techniques are not as clean as they sound

many types of transgenic animals; are they always good analogues of what you think they are?

confounding physiological/behavioural effects

c-fos expression - fMRI for rats? -- Measure expression of c-fos as an indirect marker of neuronal activity - c-fos often expressed when neurons fire action potentials.

"Occasionally when a neuron is stimulated a reaction cascade occurs that affects the expression of genes. One gene that is often immediately induced is c-fos. This is followed by an increase in c-Fos protein, that reaches peak concentrations approximately 90 minutes after stimulation."

Give critical behavioural experience, remove brain, isolate relevant area and then using c-Fos antibody evaluate level of c-Fos protein in target (and control) areas

Patterns of brain activation associated with contextual conditioning to methamphetamine in mice. Rhodes et al., 2005

c-fos expression - limitations

even if an accurate measure of neuronal activity in a particular area, which neuron? excitatory or inhibitory?

sometimes identifying adequate control procedure very difficult - how can you do within subject design?

not temporally specific

Reversible inactivation -- can temporarily inactivate certain brain areas with various types of anaesthetic e.g. lidocaine

Partial hippocampal inactivation: Effects on spatial memory performance in aged and young rats. Poe et al., 2000

can do within subject designs

Reversible inactivation - limitations

leaves no trace so have to rely on other evidence to be sure of spread

In vivo microdialysis -- can measure levels of neurotransmitter activity in a specific area of the brain while animal is engaged in task

Enhanced dopamine efflux in the amygdala by a predictive but not a nonpredictive stimulus: facilitation by prior repeated d-amphetamine. Harmer & Phillips., 1999

In vivo microdialysis - limitations

limited by size of probe

no fine temporal discrimination - looking at release over a long period in each sample

Animal models of pathological states, to understand them further and devise treatments. Various types:

complete model of syndrome – actually reproduce syndrome (but how do you know, given most are subjectively defined e.g. depression, and definition always changing – DSM 97 etc)

e.g. learned helplessness

partial model of syndrome (based on objective symptoms) – concentrate on one specific and easily identified symptom

e.g. amphetamine model of schizophrenia – based on fact it produces symptom-like behaviour

http://www.acnp.org/g4/GN401000076/CH.html

models that only predict treatment efficacy - pharmacological isomorphism; implies no real understanding, and no ability to develop new treatment... e.g. train animal to recognise one effective drug, and then see which others will substitute

models based on operationally defined psychological construct that is supposedly affected by disorder e.g. anhedonia core symptom of depression and schizophrenia, modelled by less tendency to eat sucrose


Topical examples

transgenic models e.g of schizophrenia – various dopamine knockout mice

Alzheimer’s disease – that reproduce characteristic plaques and tangles

can look for cognitive deficits that occur before -amyloid neuropathology kicks in – critical for early diagnosis

Animal models should have:

predictive validity - allows accurate predictions in human analogue?

e.g. does it predict therapeutic value of drugs in humans?

e.g. do other variables affect animal model and humans the same?


construct validity - does it do what it says on the tin?

often don't know - because don't understand the condition yet - that's the point of the exercise!

thus hard to know - constant refinement


aetiological validity - is cause of effect the same as in humans

but often don't know aetiology of conditions in man - that may be what the animal model is designed to establish

transgenics help


convergent/discriminant validity - defined with relation to other

tests

does it agree with tests for the same thing, and differ from tests for different things?


face validity - does it look right?

poor criterion - species differences; very superficial and possibly irrelevant features emphasised


Ethical Issues

Peter Singer "Animal Liberation" (1975). Argues on basis of utilitarian philosophy - the morality of action depends on whether it results in pain or pleasure. Whether an organism's feelings should be considered in this way depend on the concept of "personhood" - "A thinking intelligent being that has reason and reflection and can consider itself as itself, the same thinking thing, in different times and places." (from John Locke's Essay on Human Understanding, 1689). As animals are sentient beings, then it is species-ist to omit them from this equation - their feelings count too. Thus a healthy nonhuman primate could be considered a person in this sense -- whereas a brain damaged human infant cannot. "Should the baby live: the problem of handicapped infants"

Not all his views are popular...

Ethical Issues

Note the alternative "contractarian" moral view, according to which only those who have the ability to enter into a moral contract can be considered within the moral framework. This would exclude animals from this analysis.

I can agree with my human enemy that we will not kill each other, but cannot enter into such an agreement with an animal. So given they will kill you if they can, is it OK to kill them?

Singer's way of thinking now influences the legislation on animal experimentation in many countries, including the UK. Animal suffering is taken into account when giving permission to undertake experiments.

but remember much research does not cause suffering

Legislative Framework in UK

The use of animals in scientific procedures is regulated by the Animals (Scientific Procedures) Act 1986, which is widely viewed as the most rigorous piece of legislation of its type in the world.

Under the 1986 Act, both personal and project licences are required. These ensure that those doing the work are qualified and suitable; that alternatives to animals are used wherever possible; that the number of animals used is minimised; and that any suffering or other harmful effects experienced by the animals have been weighed against the potential benefits (to humans or animals). Special conditions control and minimise any pain or suffering. In addition, work can only be carried out at designated establishments which meet high standards and which have suitable veterinary and animal welfare personnel.

http://scienceandresearch.homeoffice.gov.uk/animal-research/animal-testing-faqs/)


If you want to work on a project involving animals using a protocol that is classified as an experiment (as mild as maintaining a rat at less than 85% of its ad lib body weight) then you must hold a Personal Licence

To obtain one of these you must possess knowledge of the legislation governing animal use, and be competent in the relevant procedures, including euthanasia. To attain this you must:

(i) go on a Home Office Training course (four levels depending on what skills you need

(ii) pass an assessment and exam


In order to be responsible for a research programme using animals on a licenced protocol, a researcher must apply for a

Project Licence, which lasts for five years.

To obtain one of these you must go on another course (1-2 days) and pass an extended assessment.

Then you must submit an application for a Project Licence.

Bottom line is that project licence holder is legally responsible for welfare of animals in his experiments.


Project Licence Application requires the following information

Background of work,

objectives

potential benefits

Justification of research project is done on the basis of a cost-benefit analysis - basically research that is unpleasant for an animal is only permitted if there is a very good reason for it.


2. Description of plan of work, including

(i) justification of research methods

(ii) justification of particular animal model employed

(iii) explanation of how proposed experimental protocols will allow research objectives to be achieved

(iv) an illustrative experiment

(v) explanations of how you are addressing the issues of reduction, refinement and replacement


3. Description of each experimental protocol employed, including

(i) number of animals ("experiments") employed

(ii) estimate of severity

(iii) precise description of what happens to animal

Following is an excerpt from a project licence protocol to induce mild food deprivation (different from what you would impose on a pet?)

Food Deprivation schedule: Each animal is weighed, normally daily, and given a restricted amount of food (approximately 5g of standard diet; this is sufficient to ensure a gradual decline in body weight so that the target weight is achieved over no less than seven days. Thereafter the daily ration is increased to approximately 5g/100g body weight, so that the target weight is maintained. In no case is body weight allowed to fall below 80% of the ad libitum level of an age- and sex-matched control. If the animal is not in an experiment, or about to start one, ad lib food will be given.

Appetitive behavioural training and testing. Animals receive normally daily sessions in the operant chambers; multiple daily sessions will be separated by at least an equivalent period of time in the home cage. The maximum session duration in a 24-hour period would be 14 hours. For sessions longer than three hours water will be made available in the chambers. Two paradigms are used. In instrumental tasks the animal operates a manipulandum (e.g., a response lever) for a reward. In classical conditioning similar rewards are delivered without any response being required. In both cases various stimuli or combinations of stimuli (e.g., auditory, visual or thermal cues, or contextual cues provided by the experimental chamber; see section 18a) may signal the occurrence or nonoccurrence of reward. Behaviour in the presence of these cues is monitored by a computer and recorded. The maximum duration of this protocol would be one year.


3. Description of each experimental protocol employed, including

(i) number of animals ("experiments") employed

(ii) estimate of severity

(iii) precise description of what happens to animal

(iv) description of possible adverse effects, likely incidence, and proposed methods of prevention

Food deprivation. Food deprivation procedures produce weight loss that is monitored by weighing (normally daily) and regulated by controlled feeding. The deprivation levels used are enough to ensure that the animals will work for food reward and produce no adverse effects (life expectancy of laboratory rats maintained at 80% ad lib weight is longer than that for rats maintained on ad lib feeding -- cf., Vitousek, Gray & Grubbs, 2004). As rodents continue to increase in weight throughout life, the target weight for experiments that take longer than three weeks to perform is adjusted for the projected increase in the 100% weight, at two-three weekly intervals over the course of the experiment; the projected increase in ad lib weight is added to the original ad lib weight, and a new 80% value is calculated. In all cases the motivation of the animals will be carefully monitored; if their performance is satisfactorily motivated for the purpose of the experiment with a deprivation régime bringing the animals to 85% rather than 80% of their ad libitum weight, (a non-regulated procedure) then this less stringent deprivation schedule will be employed. Rat weights are measured to an accuracy of 10g. If an animal's weight falls below its target level, it will be fed more than the maintenance ration until its target weight is re-attained. If this fails to produce a satisfactory increase in weight in three days, then veterinary advice will be sought, or the animal killed by a Schedule 1 method.

Appetitive behavioural training and testing. The behavioural tests employed in this protocol do not have any adverse effects (and indeed may be regarded as a form of environmental enrichment). The only possible adverse effect is that the animals might become thirsty over the course of the session. In my experience animals do not show signs of thirst (i.e. immediate drinking on return to the home cage) after shorter sessions (three hours or less). Accordingly water will be provided in the chambers for sessions of longer than three hours. If animals show signs of thirst after shorter training sessions, then water will be provided in the chambers for these shorter sessions durations also.


Most licenced work must take place in a designated establishment

Conditions of animal welfare - including cage size, numbers of animals permitted per cage (depending on animals' weight), acceptable ranges of temperature and humidity, are specified.

Home Office inspectors can arrive unannounced at any time to ensure that legislation is being adhered to. They are responsible to the Home Secretary that the establishments under their jurisdiction conduct research properly. If the project licence holder violates his licence, the Home Office inspector is implicated. Thus the Home Office inspector can shut a lab down if he deems it necessary.

Legislation: Issues arising

Many "experiments" are realistically not very aversive, and yet are legislated as stringently as those that are

Transgenic animals are regarded as experiments regardless of whether you do anything with them at all.

System of licencing based heavily on the medical model of animal research, and does not readily accommodate work in biological sciences, whose focus of interest is the animal itself

Some biologists argue that the metrics used to estimate animal unhappiness are not ethologically appropriate:


Some biologists (e.g. Barnard, 2007) argue that this approach is not appropriate:

cannot replace if you are studying the animal itself

if performing a field study, reduction may be inappropriate if this involves disrupting the "ecological integrity" of the system

refinement -- what is unpleasant for an animal? Complex -- needs to take reproductive benefit into account

e.g. if give immunosuppressant to male mice, will sleep more and be less aggressive, as this boosts their immune system. If introduce female odour, this protective mechanism overridden.


Barnard argue that as long as animal has the required freedom to act in accordance with its tendencies, suffering (in this case immunosuppression) should not be regarded as bad, because animals will naturally choose this state in order to increase probability of mating

sometimes counterintuitive results observed

e.g. environmental enrichment increases aggression, and susceptibility to infection in mice.

But for an alternative argument see Cuthill, 2007

References

Harmer, C.J., & Phillips.G.D. , (1999) Enhanced dopamine efflux in the amygdala by a predictive but not a nonpredictive stimulus: facilitation by prior repeated d-amphetamine. Neuroscience, 90, 119-130.

Hitchcott, P.K., & Phillips, G.D. (1998) Effects of intra-amygdala R(+) 7-OH-DPAT on intra-accumbens d-amphetamine-associated learning. Psychopharmacology, 140, 300-309.

Hitchcott, P.K., & Phillips, G.D. (1998) Effects of intra-amygdala R(+) 7-OH-DPAT on intra-accumbens d-amphetamine-associated learning. Psychopharmacology, 140, 458-469.

Parkinson, J.A., Willoughby, P.J., Robbins, T.W.R., & Everitt, B.J. (2000) Disconnection of the anterior cingulate cortex and nucleus accumbens core impairs Pavlovian approach behaviour: Further evidence for limbic cortical-ventral striatopallidal interactions. Behavioural Neuroscience, 114, 42-63.

Rhodes, J.S., Ryabinin, A.E., & Crabbe, J.C. (2005) Patterns of brain activation associated with contextual conditioning to methamphetamine in mice. Behavioural Neuroscience, 119, 759-771.

Zhuo et al., (2007) Early discrimination reversal learning impairment and preserved spatial learning in a longitudinal study of Tg2576 APPsw mice. Neurobiology of Aging, 28, 1248 -1257

References

Barnard, C. (2007) Ethical regulation and animal science: why animal behaviour is special. Animal Behaviour, 74, 5-13.

Boakes, R (1984). From Darwin to Behaviourism. Cambridge University Press.

Boring, E.G. (1950) A History of Experimental Psychology. New York: Appleton-Century-Crofts.

Cuthill, I.C. (2007) Ethical regulation and animal science: why animal behaviour is not so special. Animal Behaviour, 74, 15-22.

Dickinson, A. (1980) Contemporary Learning Theory. Cambridge University Press.

Hilgard E.R & Bower, G.H. (1966) Theories of Learning New York: Appleton-Century Crofts.

Singer, P. (1975) Animal Liberation: A New Ethics for our Treatment of Animals, New York Review/Random House, New York.

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