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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( ! 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( ! • 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.# # # # # # # # # # # # # # # # # # # # # # # # # 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! ! 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! ! 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(