Download psy236:(biopsychology(and(learning

PSY236:(BIOPSYCHOLOGY(AND(LEARNING( 1!
!
Behaviourial(Neuroscience:(Genetics(
Refer(to:(Kalat(–(Chapter(4((Genetics)and)Evolution)of)Behaviour,)pp.)104;116)(
(
Behaviour(is#the#response#of#an#individual,#group#or#species#to#stimuli#(trigger)#in#the#
environment.(
#
Why#do#people#(or#other#species)#respond#differently#to#a#similar#environmental#
trigger?#
#
Their#genetic#make=up#(nature)#
Environmental#factors#
(nurture/experience)#
= Evolution#(e.g.#human#vs.#bird)#
= How#they#are#‘feeling’#at#the#time#
= Parental#traits#(colour#of#skin,#height,#
(hungry,#tired,#happy,#hot,#etc.)#!#
intelligence,#ability#to#sing,#etc.).#
different#responses#for#different#
stimuli.#
= Previous#experiences#(or#taught#a#
skill#or#how#to#behave).#
= Culture.#
#
Genes(
#
Units#of#heredity#that#maintain#their#structural#identity#from#one#
generation#to#another.#
#
Part#of#chromosomes,#composed#of#DNA#(deoxyribonucleic#acid).#
#
They#are#important,#as#they#drive#the#function#of#our#cells.#
Chromosomes(
Structure#of#genes,#i.e.#contain#our#genetic#material#and#DNA.#
#
Within#the#human#system,#there#are#46#chromosomes,#paired#in#
23#pairs.#Duplicated#chromosomes#are#referred#to#as#‘sister#
chromatids’.#
" It#is#unusual#to#see#chromosomes#as#single#structures,#as#they#
are#usually#in#a#replicated#stage.#Therefore,#we#often#see#them#
joined#together,#at#the#centromere.#
" As#a#rule,#genes#come#in#pairs#because#they#are#aligned#along#
chromosomes#(that#also#come#in#pairs,#as#mentioned#above).#
#
Female#chromosomes#=#XX;#Male#chromosomes#=#XY#(therefore,#
they#determine#the#sex#of#the#baby#–#if#they#produce#X#=#female#
[XX],#if#they#produce#Y#=#male#[XY]).#
(DNA(
Double#strands#of#nucleotide#‘base=pairs’#on#chromosomes.#DNA#
(deoxyribonucleic( contains#four#‘bases’:#thymine#(T)#=#adenine#(A);#guanine#(G)#=#
acid)(
cytosine#(C).##
#
#
4! PSY236:(BIOPSYCHOLOGY(AND(LEARNING(
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Dominant(
Recessive(
(
A#recessive#gene#
affects#
development#
only#in#the#
absence#of#the#
dominant#gene.#
Genetic(changes(
Epigenetics##
Heritability(is#an#
estimate#of#the#
amount#of#
variation#that#is#
due#to#genetic#
variation,#as#
opposed#to#
environmental#
variation.(
Evolution(of(
Behaviour##
#
Evolution#is#a#
change#over#
generations#in#
the#frequencies#
of#various#genes#
in#a#population.#
Dominant#genes#only#require#
ONE#gene#to#be#present#on#
the#chromosome,#to#produce#
that#characteristic.#
Recessive#genes#require#
BOTH##genes#to#be#present#on#
the#chromosome,#to#produce#
#
that#characteristic.#
#
Recessive#characteristics#can#
only#be#seen#in#homozygous#
conditions.#For#example,#a#
gene#for#brown#eyes#is#
dominant#and#a#gene#for#blue#
eyes#is#recessive.#If#you#have#
one#gene#for#brown#eyes#and#
one#for#blue,#the#result#is#
brown#eyes.#
Genes#change#in#several#ways.#One#way#is#by#mutation:#alterations#
or#deletions#of#genetic#sequence.#
#
One#common#example#is#Down#Syndrome,#caused#by#the#addition#
of#a#third#chromosome#at#Chromosome#21#(therefore,#Down#
Syndromes#get#additional#gene#and#end#up#with#47#instead#of#46.#
Deals#with#changes#in#gene#expression,#for#example,#the#genes#
active#in#your#brain#are#not#the#same#as#those#active#in#your#lungs#
or#kidneys.#At#puberty,#silent#genes#become#much#more#active.#
Essentially,#chemicals#active#or#deactivate#parts#of#chromosomes.#
High(heritability#=#behavior#is#greatly#determined#by#genes,#e.g.#
organisation#and#cleanliness#skill#“just#like#her#mum”.##
#
Low(heritability#=#behavior#is#greatly#determined#by#
environment,#e.g.#surgeons#have#been#trained#to#be#organised#
and#clean.#
#
Essentially,#the#less#an#effect#of#our#environment#on#a#particular#
behavior#shows#that#the#behavior#has#high#heritability.#
Natural#selection#=#survival#(and#reproduction#of#the#fittest),#
whereby#each#gene#may#be#kept#or#eliminated#to#help#survival#of#
a#species.#How#does#this#occur?#For#example,#if#an#animal#carries#a#
gene#to#cause#slow#running,#they#are#likely#to#be#caught#and#
eating,#limiting#their#breeding#capacity#!#gene#slowly#dies#out.#
#
Genetic#traits#that#produce#an#advantage#over#others#in#the#same#
species#will#be#kept#(caused#through#breeding#by#the#survivors).#
18! PSY236:(BIOPSYCHOLOGY(AND(LEARNING(
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•
The#reason#why#it#does#this#is#to#help#the#action#potential#go#along#the#length#of#
the#axon,#which#will#result#in#neurotransmitter#release#at#the#other#end.#It#needs#
to#occur,#as#one#neuron#will#not#be#able#to#talk#to#another#neuron.#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
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Summary(–(Resting(Membrane(Potential(
(
• The#resting#membrane#potential#(RMP)#is#produced#by#the#electrochemical#
gradient#between#the#intracellular#and#extracellular#fluid#bordering#the#
phospholipid#bilayer#membrane#of#the#neuron.#
• Cells#can#have#different#RMP’s,#commonly#neurons#have#an#RMP#of#=70mV.#
• At#rest,#the#inside#of#the#neuron#is#negative#due#to#many#proteins#and#chloride#
ions#which#have#a#negative#charge,#and#proteins#can#not#leave#the#neuron.#
• At#rest,#inside#the#neuron#there#is#a#high#concentration#of#K+#ions#and#a#low#
concentration#of#Na+.#Outside#of#the#cell#is#the#opposite#
• K+#ions#channels#are#open#(not#the#voltage=gated#ones)#which#allows#
• K+#to#enter#the#cell#(electrical#gradient)#or#to#leave#the#cell#(concentration#
gradient)#
• Voltage=gated#Na+#ion#channels#and#K+#ion#channels#are#not#open#
• The#membrane#potential#is#regulated#by#the#Na+/K+#pump.#Adenosine#
triphosphate#(ATP;#energy)#is#required#to#pump#3Na+#ions#out#and#2K+#ions#in#
#
(
(
PSY236:(BIOPSYCHOLOGY(AND(LEARNING( 33!
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Substance(Abuse(
(
Why(do(people(take(drugs?((
(
Drugs#make#people#feel#good.#Why?#Drugs#stimulate#the#mesolimbic#dopamine#
‘reward’#pathway#(Ventral#Tegmental#Area/VTA#[dopamine#cell#bodies]#!#Nucleus#
Accumbens#[Major#reward#area]).##
#
What#is#reward?#Reward#is#positive#reinforcement,#influencing#you#to#repeat#the#behaviour#in#the#future.#
The#initial#exposure#to#certain#drugs#will#produce#feelings#of#reward#in#the#form#of#elation,#excitement#
and/or#relaxation.##
#
It#is#when#the#usage#is#reinforced#(repeated)#that#becomes#known#as#‘a#drug#of#abuse’.#
Drugs#of#abuse#increase#dopamine#neurotransmission.##
• The#rewarding#effect#of#abused#drugs#is#inhibited#by#dopamine#receptor#
antagonists#and#lesions#of#dopamine#cells#(6=OHDA).#
(
Chronic(Drug(Effects( o
•
•
•
•
!
Activity#of#neurons#in#the#ventral#tegmental#area#signals#a#reward#prediction#error.#The#
anticipation#of#reward#produces#a#large#increase#in#dopamine.#The#reward#itself#produces#
some#dopamine#release,#yet#an#error#in#the#value#of#the#reward#has#more#of#an#effect#on#
dopamine.#How?#The#pharmacology#of#drugs#to#enhance#dopamine#levels#signals#to#the#brain#
that#the#drug#is#much#‘better(than(expected’.#
Paranoid#
psychosis#(cf.#
schizophrenics).#
Seizures.#
• On#the#other#hand,#however,#all#drugs#of#abuse#have#serious#side#effects#from#
Depression#and#
repeated#abuse:#namely,#addiction,#psychosis,#depression#and#anxiety.#
anxiety.#
#
MPTP#(cf.#
Parkinson’s#ALL(DRUGS(OF(ABUSE(INCREASE(DOPAMINE((DA)(IN(THE(NUCLEUS(ACCUMBENS((NA).(
disease).#
INCREASED(DOPAMINE(=(LOVE((AND(ADDICTION)(OF(DRUGS(
(
(Pyschoc)(Stimulants:#arouses#or#accelerates#activities#in#the#brain.#(stimulates#
monoamines).#
#
Work#in#the# • Cocaine((‘crack’).#Increases#dopamine#in#synaptic#cleft#by#blocking#DAT#(dopamine#transporter).#
same#regions,#
(Cocaine(blocks(the(DAT)#
including#the# • Amphetamine((‘speed’).#Amphetamine#derivatives#include#methamphetamine#(‘ice’#and#‘speed’),#
striatum,#
which#causes#
stereotypy#or#
repetitive#
movements#
(e.g.#chewing,#
moving#
fingers,#
moving#head#
side#to#side.#
methylenedioxymethamphetamine#(MDMA#or#‘ectasy’)#and#methylphenidate#(‘ritalin’#for#ADHD#
patients).#These#are#considered#worse#than#cocaine,#as#they#increase#extracellular#monoamines#by#
reversing#(as#opposed#to#blocking)#monoamines#and#SERT#(serotonin#transporter),#consequently#
causing#a#massive#inflation#in#dopamine#levels.#(Amphetamines(reverse(the(DAT).(
#
o Short=term#effects#of#stimulants:#euphoria,#increased#alertness,#increased#self=
confidence#and#increased#energy.#In#particular,#‘ectasy’#promotes#a#‘touchy=feely’#
feeling#which#promotes#closeness#to#others.#
o Long=term#effects#of#stimulants:#seizures,#depression,#anxiety,#paranoia,#psychosis#
and#neurotoxicity.#
(
Narcotics:(induces#narcosis#(sleep#or#stupor)#=#numbing.##
#
PSY236:(BIOPSYCHOLOGY(AND(LEARNING( 45!
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Introduction(to(Learning(
•
•
•
•
•
(
Learning(
(
Learning#is#identified#by#a#change#in#behaviour#–#either#the#acquisition#of#a#new#
response#or#the#suppression#of#an#existing#response.#
A#major#feature#of#learning#that#makes#it#different#from#other#forms#of#behaviour#
change#is#that#it#is#relatively#long#lasting.#
Yet,#not#all#long=term#changes#in#behaviour#are#due#to#learning,#e.g.#maturation.#
Behavioural#changes#due#to#learning,#and#changes#due#to#maturation#ARE#interrelated.#
However:#
(1) Practice#is#not#needed#for#maturation#(unlike#learning).#
(2) The#one#maturational#process#can#produce#changes#in#a#variety#of#situations#(unlike#
learning,#where#changes#are#limited#to#the#practice#response/similar#context).#
In#essence,#learning#is#‘a#relatively#enduring#change#in#the#potential#to#engage#in#a#
particular#behaviour#resulting#from#experience#with#environmental#events#specifically#
related#to#behaviour.#
#
Behavioural(and(Cognitive(Approaches(to(Learning(
(
The#field#of#learning#is#frequently#associated#with#a#general#approach#to#psychology#
called#‘behaviourism’.#Two#characteristics#of#the#behavioural#approach:#
(1) Heavy#reliance#on#animal#subjects.#Why#animal#subjects?#
- In#research#with#humans,#subject(effects#can#pose#serious#problems.#
- Convenience((easy/inexpensive#to#care#for;#always#turn#up).#
- Their#environment(can#be#controlled(to#a#greater#degree#than#with#wild#animals#
or#humans.#
- Comparative#simplicity((we#have#a#better#chance#of#discovering#basic#
behavioural#principles#by#examining#animals#that#are#less#complex#and#
intelligent).r#
(2) Emphasis#on#external#events#(environmental#stimuli#and#overt#behaviours).#
- The#term#behaviorism#was#coined#by#J.B.#Watson.#He#had#criticised#research#
techniques#that#had#prevailed#in#the#field#of#psychology#in#early#1900s#(e.g.#
introspection).#
According#to#Watson’s#logic:#
i.####We#want#psychology#to#be#a#science.#
ii.###Sciences#only#deal#with#events#that#we#can#observe.#
iii.##Psychology#then#must#deal#with#observable#events#!#Observable#events#in#
psychology#are#the#stimuli(that#a#person#senses#and#the#responses(a#person#
makes.#
- B.F.#Skinner#criticised#the#use#of#unobservable#events#in#psychological#theory,#
arguing#that#it#is#dangerous#and#unnecessary#to#point#to#some#unobservable#
event,#or#intervening(variable,(as#the#cause#of#behaviour.##
PSY236:(BIOPSYCHOLOGY(AND(LEARNING( 55!
!
•
•
•
•
#
Basic(conditioning(phenomena(
(
Acquisition:#the#part#of#conditioning#in#which#the#subject#first#experiences#a#series#of#
CS=US#pairings,#during#which#the#CR#gradually#appears#and#increases#in#strength.#
Asymptote:#the#stable#maximum#level#of#CR#that#is#gradually#approached#as#
conditioning#proceeds.#
Extinction:#what#is#the#effect#of#the#passage#of#time#and#how#permanent#is#a#CR?#By#
repeatedly#presenting#the#CS#without#the#US#will#cause#the#CR#to#eventually#disappear.#
However,#whatever#happens#during#extinction,#it#is#not#simply#an#erasure#of#previous#
learning,#as#shown#by#(1)#spontaneous#recovery,#(2)#disinhibition#and#(3)#rapid#
reacquisition.#
(1) Spontaneous(recovery:#following#an#acquisition#phase#on#day#1#and#an#extinction#
phase#on#day#2,#if#the#animal#is#returned#to#the#chamber#on#day#3#for#another#series#
of#extinction#trials#we#are#likely#to#see#some#CR.#
(
Pavlov#treated#
spontaneous#recovery#as#
proof#that#the#CS=US#
association#is#not#fully#
destroyed#in#extinction#
procedure.#Several#
theories#of#spontaneous#
recovery#have#recently#
developed…#
INHIBITION#THEORY#states#that#after#extinction#is#complete,#the#subject#is#left#with#
two#counteracting#associations:#
i.###The#CS=US#association#formed#during#acquisition#is#the#excitatory#association.#
ii.###A#parallel#but#inhibitory#association#develops#during#extinction.##
Upon#completion#of#extinction,#the#effects#of#these#two#associations#cancel#out.#
However,#newly#formed#inhibitory#associations#are#more#fragile#than#excitatory#
associations.#
At#the#end#of#Day#2#the#inhibitory#association#is#strong#enough#to#fully#counteract#the#
excitatory#association.##But#between#Day#2#and#Day#3#the#inhibitory#association#is#
weakened#because#some#time#has#passed.#Further#extinction#trials#on#Day#3#
strengthen#the#inhibitory#association#so#the#CR#again#disappears.###
#
Practical(3(–(CLASSICAL(CONDITIONING(
o Before(the(rate(
of(bar(pressing(
before(the(CS(
comes(on(to(
the(amount(of(
bar(pressing(to(
during(the(
presentation(
of(CS.((
(
Introduction(to(Classical(Conditioning(
(
! Conditioned(stimulus(=(CS(
! Unconditioned(stimulus(=(US(
! Conditioned(response(=(CR(
! Unconditioned(response(=(UR(
(
• The(form(of(learning(that(results(when(two(stimuli(reliably(occur(in(a(
sequence(so(that(the(first(predicts(the(occurrence(of(the(second.((
• Typically,(the(stimulus(that(occurs(first((CS)(such(as(a(bell(is(of(less(biological(
importance(to(the(organism(than(on(the(one(that(follows((US)(such(as(food(
placed(in(the(mouth(of(foodAdeprived(dogs.(
• The(US(initially(possesses(the(capacity(to(elicit(an(obvious,(easy(to(measure(
response((UR)(such(as(chewing,(swallowing(and(salivation(elicited(by(food(in(
a(hungry(dog’s(mouth.(
• The(classical(conditioning(acquisition(procedure(consists(of(REPREATED(
pairing(of(CS(with((before)(US.(As(a(consequence,(the(CS(gradually(acquires(
the(capacity(to(elicit(a(new(learned(response(called(the(conditioned(response(
or(CR.(
• Usually,(but(not(always,(this(CR(resemble(the(UR(in(the(sense(that(the(CR(
consists(of(certain(components(of(the(UR((e.g.(salivation).((
• Sniffy(Lite(simulates(a(form(of(classical(conditioning(called(the(conditioned(
emotional(response((CER).(The(CER(provides(an(experimental(preparation(
for(studying(the(acquisition(of(a(very(important(and(interesting(response(–(
fear(
• Conditioned(Emotional(Response(paradigm:(a(form(of(classical(conditioning(
in(which(a(CS(acquires(the(capacity(to(elicit(freezing(and(other(fearArelated(
behaviours(as(the(result(of(being(paired(with(an(aversive(US.(
• We(can(measure(conditioned(fear(responses(in(two(ways:((
1. Movement(ratio:(the(proportion(of(time(during(each(presentation(o(the(CS(
that(Sniffy(is(manifesting(freezing(and(other(fearArelated(responses.(
2. Suppression(ratio:(requires(that(Sniffy(first(be(trained(to(press(the(bar(in(
his(operant(chamber(to(obtain(food(reinforcement.(
• The(basic(idea(is(to(compare(the(rate(of(bar(pressing(during(the(CS(to(that(
during(the(period(of(time(immediately(preceding(presentation(of(the(CS.(
• If(the(CS(elicits(no(fear(response,(the(number(of(bar(presses(during(these(two(
time(periods(should(be(about(the(same.(But(if(the(CS(suppresses(bar(pressing,(
then(Bar(Presses(During(CS(will(be(less(than(Bar(Presses(Pre(CS.(
• To(get(a(quantitative(measure(of(suppression(of(the(bar(pressing(in(response(
to(the(CS,(the(suppression(ratio(is(expressed(as:(
(
(
(
(
(
Practical(4(–(OPERANT(CONDITIONING(
(
Introduction(to(Operant(Conditioning(
(
• Skinner(proposed(that(psychologists(should(seek(to(discover(relationships(
between(the(environment(and(behaviour(without(speculating(about(what(
goes(on(inside(the(organism.(
• Skinner(distinguished(between:(
o Elicited(behaviour(is(the(specific(result(of(presenting(a(particular(stimulus.(
o Emitted(behaviours(are(responses(that(occur(without(any(readily(
identifiable(eliciting(stimulus((e.g.(there(is(no(stimulus(that(will(reliably(
elicit(grooming(movements(or(barking(from(all(normal(dogs(in(the(same(
way(placing(food(on(a(dogs(tongue(will(elicit(salivation).(
• The(scientific(question(to(which(Skinner(sought(experimental(answers(to(
was:(What(controls(the(frequency(of(emitted(behaviours?((
• To(address(this(question,(he(developed(the(operant(chamber(in(which(he(
thought(it(would(be(possible(to(discover(how(the(environment(determines(
the(frequency(with(emitted(behaviours(are(produced.(
• In(an(operant(chamber(animals(are(trained(in(an(experimental(situation(in(
which(the(opportunity(to(perform(some(response((e.g.(press(a(lever)(is(
continuously(available…(
• Operant(conditioning:(a(type(of(learning(in(which(the(future(probability(of(a(
behaviour(is(affected(by(its(consequences.(
• Reinforcer:(a(consequence(that(is(used(to(strengthen(a(behaviour.(
• Reinforcement:(a(procedure(that(makes(a(response(more(likely(to(be(
repeated(under(similar(circumstances(in(the(future.(
• That(is,(the(term(reinforcer(refers(to(the(actual(consequence(of(a(behaviour;(
the(term(reinforcement(refers(to(the(process(or(procedure(of(strengthening(a(
behaviour(by(instituting(this(consequence.(
• Positive(reinforcement(is(a(behaviour(strengthening(procedure(in(which(the(
occurrence(of(a(behaviour(is(followed(by(the(presentation(of(a(stimulus((one(
that(is(usually(considered(pleasant(or(rewarding).(
• Negative(reinforcement(is(a(behaviour(strengthening(procedure(in(which(a(
stimulus(is(removed(or(omitted((one(that(is(usually(considered(unpleasant(or(
aversive)(if(the(behaviour(occurs.(
• The(word(positive(means(only(that(the(behaviour(has(resulted(in(something(
being(presented(or(added;(the(word(negative(means(only(that(the(behaviour(
has(resulted(in(something(being(removed(or(subtracted.(
• Another(dimension(concerns(whether(the(reinforcing(power(of(the(stimulus(
is(intrinsic(or(learned.(Food(is(a(good(example(of(a(stimulus(whose(
reinforcing(power(is(intrinsic;(animals(require(no(special(training(for(food(to(
acquire(the(capacity(to(act(as(a(positive(reinforcer.(Stimuli(whose(
effectiveness(as(reinforcers(requires(no(special(training(are(said(to(be(
primary(reinforcers.(
• Other(stimuli(that(lack(intrinsic(reinforcing(power(can(acquire(the(capacity(to(
act(as(reinforcers(if(they(are(paired(with(primary(reinforcers.(For(example,(
there(is(nothing(intrinsically(reinforcing(about(money(but(people(learn(to(
treat(money(as(a(powerful(positive(reinforcer(because(of(its(paring(with(