Psychology 250Psychology 250

Lecture 12Lecture 12

Kevin R SmithKevin R Smith

Three Types of BehaviorThree Types of Behavior Reflexes: involuntary Reflexes: involuntary

responses to stimuliresponses to stimuli Instincts: stereotyped Instincts: stereotyped

responses triggered responses triggered by environmental by environmental stimulistimuli

Learning: a relatively Learning: a relatively permanent change in permanent change in behavior due to behavior due to experienceexperience

© Renee Purse/Photo Researchers, Inc.

Types of LearningTypes of Learning

Nonassociative learning: a change in Nonassociative learning: a change in the magnitude of response to the magnitude of response to environmental eventsenvironmental events• HabituationHabituation• SensitizationSensitization

Associative learning: a connection Associative learning: a connection between two elements or eventsbetween two elements or events• Classical conditioningClassical conditioning

Habituation and SensitizationHabituation and Sensitization Habituation Habituation

• The response to steady or repeated The response to steady or repeated stimulus decreases over timestimulus decreases over time

• Example: You don’t hear your air Example: You don’t hear your air conditioner after it’s been running awhileconditioner after it’s been running awhile

SensitizationSensitization• The experience of one stimulus heightens The experience of one stimulus heightens

the response to a subsequent stimulusthe response to a subsequent stimulus• Example: People are “jumpy” following Example: People are “jumpy” following

natural disasters, like earthquakesnatural disasters, like earthquakes

Classical Conditioning and PavlovClassical Conditioning and Pavlov

Dogs eating habitsDogs eating habits• Noticed that the dogs salivate prior to Noticed that the dogs salivate prior to

getting their foodgetting their food• Measured the amount of salivation that Measured the amount of salivation that

occurs when the dogs are anticipating occurs when the dogs are anticipating foodfood

Anticipation cues were Pavlov at firstAnticipation cues were Pavlov at first• Changed to a toneChanged to a tone

Pavlovian ConditioningPavlovian Conditioning

Before TrainingBefore Training• No salivation to a toneNo salivation to a tone• Salivation to meat onlySalivation to meat only

After TrainingAfter Training• Salivation to a toneSalivation to a tone

Classical ConditioningClassical Conditioning

A conditioned stimulus (CS) is an initially A conditioned stimulus (CS) is an initially neutral stimulus that acquires the ability neutral stimulus that acquires the ability to signal important biological eventsto signal important biological events

An unconditioned stimulus (UCS) is an An unconditioned stimulus (UCS) is an event that elicits a response without prior event that elicits a response without prior experienceexperience

A conditioned response (CR) is a learned A conditioned response (CR) is a learned reaction to a CSreaction to a CS

An unconditioned response (UCR) is an An unconditioned response (UCR) is an unlearned reaction to a UCSunlearned reaction to a UCS

Using Using Aplysia Californica Aplysia Californica to Study to Study Learning Learning

The gill is used for The gill is used for breathingbreathing

The gill can be covered with The gill can be covered with the mantle shelfthe mantle shelf

Waste and seawater are Waste and seawater are released through the siphonreleased through the siphon

The gill-withdrawal reflex The gill-withdrawal reflex occurs when touching the occurs when touching the siphon produces a siphon produces a retraction of the gillretraction of the gill• Touching the siphon Touching the siphon

repeatedly yields a repeatedly yields a decrease in the gill decrease in the gill withdrawal reflex: withdrawal reflex: HabituationHabituation

Eric Kandel and Habituation in Eric Kandel and Habituation in AplysiaAplysia

The siphon is served by 24 sensory The siphon is served by 24 sensory neurons, whose cell bodies are in the neurons, whose cell bodies are in the abdominal ganglionabdominal ganglion

Siphon sensory neurons form Siphon sensory neurons form synapses with:synapses with:• excitatory and inhibitory interneuronsexcitatory and inhibitory interneurons• six motor neurons serving the gillsix motor neurons serving the gill

Possible Hypotheses for Possible Hypotheses for HabituationHabituation

Do sensory neurons become less responsive?Do sensory neurons become less responsive?• Single cell recordings from sensory neurons did not decrease Single cell recordings from sensory neurons did not decrease

with repeated touching of the siphonwith repeated touching of the siphon

Daniel L. Geiger/SNAP

More HypothesesMore Hypotheses

Does the gill muscle lose its ability to Does the gill muscle lose its ability to contract?contract?• Electrical stimulation of the motor Electrical stimulation of the motor

neurons produced muscle contraction, neurons produced muscle contraction, even after habituationeven after habituation

Do changes occur at the synapses Do changes occur at the synapses between the sensory and motor between the sensory and motor neurons?neurons?

Kandel’s Explanation of Kandel’s Explanation of HabituationHabituation

Repeated siphon touches Repeated siphon touches reduce entry of calcium reduce entry of calcium into sensory neurons, into sensory neurons, which release less which release less neurotransmitterneurotransmitter

Smaller EPSPs occur in Smaller EPSPs occur in interneurons and motor interneurons and motor neuronsneurons

Motor neurons produce Motor neurons produce weaker response, leading weaker response, leading to less gill withdrawalto less gill withdrawal

AplysiaAplysia also show sensitization also show sensitization

After a electrical shock to the head or After a electrical shock to the head or tail, there is an increased gill-tail, there is an increased gill-withdrawal response when the withdrawal response when the siphon is touchedsiphon is touched

Sensitization in Sensitization in AplysiaAplysia

Shocking the tail stimulates Shocking the tail stimulates interneurons that form synapses with interneurons that form synapses with sensory neurons serving the siphonsensory neurons serving the siphon

Sensory neurons release more Sensory neurons release more neurotransmitter onto motor neurotransmitter onto motor neurons, and the gill retracts stronglyneurons, and the gill retracts strongly

Long-term ChangesLong-term Changes

Normal Normal Aplysia Aplysia showed showed 1300 axon terminals on 1300 axon terminals on sensory neuronssensory neurons

Aplysia Aplysia experiencing experiencing sensitization had sensitization had 2800 terminals2800 terminals

Aplysia Aplysia experiencing experiencing habituation had 800 habituation had 800 terminalsterminals

Classical Conditioning in Classical Conditioning in AplysiaAplysia

Electrical shock to the tail leads to Electrical shock to the tail leads to gill-withdrawal reflexgill-withdrawal reflex

Touching the mantle alone does not Touching the mantle alone does not trigger anythingtrigger anything

Pairing the mantle with the shock Pairing the mantle with the shock leads to gill-withdrawal reflexleads to gill-withdrawal reflex

After learning, touching the mantle After learning, touching the mantle alone leads to gill-withdrawal reflexalone leads to gill-withdrawal reflex

Classical ConditioningClassical Conditioning

Mechanisms for Classical Mechanisms for Classical ConditioningConditioning

Touching the mantle leads to NT releaseTouching the mantle leads to NT release• Amount released is too small to get a gill-Amount released is too small to get a gill-

withdrawal reflexwithdrawal reflex Touching the tail leads to an increase in Touching the tail leads to an increase in

the NT released at the gill-withdrawal the NT released at the gill-withdrawal reflexreflex

After frequent pairingsAfter frequent pairings• More NT is released when the mantle is More NT is released when the mantle is

touched by itselftouched by itself

Conditioned Emotional Conditioned Emotional Responses and the AmygdalaResponses and the Amygdala

Typical Paradigm:Typical Paradigm:• Tone (CS+) followed by shock (UCS) results in Tone (CS+) followed by shock (UCS) results in

reduced feeding (CR) in ratsreduced feeding (CR) in rats Recording during training shows an increased Recording during training shows an increased

response of the amygdala to the toneresponse of the amygdala to the tone Lesions of the basolateral nucleus of the Lesions of the basolateral nucleus of the

amygdala prevent the learning of emotional amygdala prevent the learning of emotional responsesresponses

Blocking NMDA receptors in the amygdala Blocking NMDA receptors in the amygdala prevents learning of conditioned emotional prevents learning of conditioned emotional responsesresponses

Thus: the amygdala is involved in Classical Thus: the amygdala is involved in Classical ConditioningConditioning

Learning and the CerebellumLearning and the Cerebellum

Cerebellum is involved in motor Cerebellum is involved in motor controlcontrol

Also probably involved in motor Also probably involved in motor learninglearning

Highly complex network of neurons Highly complex network of neurons controls learningcontrols learning

Long Term DepressionLong Term Depression

Long term depressionLong term depression• A weakening of a synapse that lasts hours A weakening of a synapse that lasts hours

or daysor days• Thought to be associated with learningThought to be associated with learning• Found in the cerebellum and hippocampusFound in the cerebellum and hippocampus

Long term potentiationLong term potentiation• A long lasting strengthening of a synapseA long lasting strengthening of a synapse• Thought to be associated with memoryThought to be associated with memory

Classical Conditioning of the Classical Conditioning of the Rabbit’s Nictitating MembraneRabbit’s Nictitating Membrane

A tone (CS) followed by a puff of air A tone (CS) followed by a puff of air to the eye (UCS) leads to closure of to the eye (UCS) leads to closure of the nictitating membrane (UCR)the nictitating membrane (UCR)

Activity in the lateral interpositus Activity in the lateral interpositus nucleus (LIP) of the cerebellum nucleus (LIP) of the cerebellum increases in response to the tone increases in response to the tone over trialsover trials

Human Research and the LIPHuman Research and the LIP

Humans learn classically conditioned Humans learn classically conditioned eyeblink responseseyeblink responses

PET scans show increased cerebellar PET scans show increased cerebellar activity during classical conditioningactivity during classical conditioning

Individuals with cerebellar damage Individuals with cerebellar damage have difficulty learning conditioned have difficulty learning conditioned eyeblink responseseyeblink responses

MemoryMemory

Memory refers to the storage and Memory refers to the storage and retrieval of informationretrieval of information

No absolute boundaries between No absolute boundaries between learning and memorylearning and memory

Learning and memory may be Learning and memory may be viewed as a continuumviewed as a continuum

The Atkinson-Shiffrin Model of The Atkinson-Shiffrin Model of MemoryMemory

Divisions of Long-term MemoryDivisions of Long-term Memory

Locating the Memory Trace Locating the Memory Trace (Engram)(Engram) Karl Lashley Karl Lashley

observed the effects observed the effects of lesions on rats’ of lesions on rats’ maze learningmaze learning

The larger the The larger the amount of cortex amount of cortex damaged, the more damaged, the more errors the rats madeerrors the rats made

Lashley believed Lashley believed that the engram that the engram was distributed was distributed across the cortexacross the cortex

Brain Stimulation and MemoryBrain Stimulation and Memory Wilder Penfield stimulated the cortex of Wilder Penfield stimulated the cortex of

patients undergoing surgery for epilepsypatients undergoing surgery for epilepsy 8% of the patients experienced specific 8% of the patients experienced specific

memories when their temporal lobes memories when their temporal lobes were stimulatedwere stimulated

Lead to the theory that memories could Lead to the theory that memories could be localized in the brainbe localized in the brain

Penfield’s results may have been Penfield’s results may have been influenced by the patients’ epilepsyinfluenced by the patients’ epilepsy

Patient H.M. and MemoryPatient H.M. and Memory Large areas of H.M.’s Large areas of H.M.’s

temporal lobes were temporal lobes were surgically removedsurgically removed

H.M.’s personality and H.M.’s personality and IQ were not affectedIQ were not affected

H.M. experienced H.M. experienced profound anterograde profound anterograde amnesiaamnesia• Inability to learn new Inability to learn new

informationinformation

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RetrogradeRetrograde• Loss of memories of the pastLoss of memories of the past

AnterogradeAnterograde• Inability to form new memoriesInability to form new memories

H.M.’s Memories Are Not Equally H.M.’s Memories Are Not Equally AffectedAffected

Short-term Short-term memory allowed memory allowed H.M. to converseH.M. to converse

H.M. retained the H.M. retained the ability to learn ability to learn procedural tasksprocedural tasks

H.M.’s deficits H.M.’s deficits appear in explicit appear in explicit memory tasksmemory tasks

The Delayed Nonmatching to The Delayed Nonmatching to Sample TaskSample Task

Monkeys with Monkeys with medial temporal medial temporal lobe damage do lobe damage do poorly on the poorly on the DNMS taskDNMS task

The DNMS task The DNMS task requires the requires the ability to form ability to form long-term long-term memoriesmemories

Conclusion thus farConclusion thus far

The amygdala and the cerebellum The amygdala and the cerebellum seem to play a role in forming seem to play a role in forming associations (very basic learning)associations (very basic learning)• Animal studiesAnimal studies

The temporal lobe seems to play The temporal lobe seems to play some role in memoriessome role in memories• HM and MonkeysHM and Monkeys

What about the Hippocampus?What about the Hippocampus?

The Hippocampus and The Hippocampus and MemoriesMemories

HM had major lesions to his HM had major lesions to his hippocampushippocampus• Anterograde anmesiaAnterograde anmesia

LTP occurs in the hippocampusLTP occurs in the hippocampus LTP results when synapses become LTP results when synapses become

more efficientmore efficient LTP can be demonstrated indefinitely LTP can be demonstrated indefinitely

in living animals and for hours in slices in living animals and for hours in slices of hippocampusof hippocampus

LTP Shares Characteristics with LTP Shares Characteristics with Long-term MemoryLong-term Memory

Unsure of whether LTP is the mechanism Unsure of whether LTP is the mechanism for Long term memories BUTfor Long term memories BUT• Both LTP and long-term memories last Both LTP and long-term memories last

indefinitelyindefinitely• Both LTP and long-term memories result Both LTP and long-term memories result

from very brief inputfrom very brief input• LTP is consistent with cellular learning LTP is consistent with cellular learning

models proposed by Donald Hebbmodels proposed by Donald Hebb NMDA receptors (Glutamate) closely NMDA receptors (Glutamate) closely

associated with LTPassociated with LTP

The Hippocampus and Human The Hippocampus and Human MemoryMemory

The right hippocampus is active during The right hippocampus is active during spatial memory processing and the left spatial memory processing and the left hippocampus is active during verbal hippocampus is active during verbal memory processingmemory processing

Rostral portions of the hippocampus are Rostral portions of the hippocampus are more active during encoding, and caudal more active during encoding, and caudal portions are active during retrievalportions are active during retrieval

The hippocampus does not store The hippocampus does not store memories, but transfers them from short memories, but transfers them from short to long-term storageto long-term storage

Patient N.A.Patient N.A. A fencing foil A fencing foil

produced a lesion to produced a lesion to N.A.’s left N.A.’s left dorsodorsommedial thalaedial thalammusus

N.A. experienced N.A. experienced profound anterograde profound anterograde aammnesia and sonesia and somme e retrograde aretrograde ammnesianesia

N.A.’s N.A.’s mmeemmory loss ory loss was siwas simmilar to H. ilar to H. MM.’s.’s

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The Diencephalon and MemoryThe Diencephalon and Memory

Korsakoff’s patients show anterograde and Korsakoff’s patients show anterograde and retrograde amnesiaretrograde amnesia• Thiamine deficiencies result from chronic Thiamine deficiencies result from chronic

alcoholismalcoholism• Untreated thiamine deficiencies damage Untreated thiamine deficiencies damage

dorsomedial thalamus and mamillary bodiesdorsomedial thalamus and mamillary bodies Monkeys with lesions in the dorsomedial Monkeys with lesions in the dorsomedial

thalamus have difficulties with the DNMS thalamus have difficulties with the DNMS testtest

Temporal-diencephalic circuits may process Temporal-diencephalic circuits may process long-term memorieslong-term memories

Localization of SeLocalization of Semmantic antic MMeemmoriesories

SeSemmantic antic mmeemmories are widely distributed in the ories are widely distributed in the cortexcortex

Prosopagnosia: inability to recognize common facesProsopagnosia: inability to recognize common faces

Localization of Localization of MemoriesMemories

Encoding and Encoding and retrieval retrieval mmay ay activate different activate different areasareas

Episodic Episodic MMeemmory and the ory and the CortexCortex

Greater right frontal Greater right frontal and teand temmporal activity poral activity is associated with is associated with hearing your own story hearing your own story rather than another rather than another person’sperson’s

In source aIn source ammnesia, a nesia, a patient forgets when patient forgets when and where a and where a mmeemmory ory was forwas formmeded

Episodic Episodic mmeemmory is ory is superior in fasuperior in fammilies ilies where left-handedness where left-handedness is cois commmmonon

Short-terShort-termm MMeemmory and the Cortexory and the Cortex The prefrontal cortex The prefrontal cortex mmay be involved with ay be involved with

short-tershort-termm mmeemmoryory Patients with prefrontal daPatients with prefrontal dammage do poorly on age do poorly on

the Wisconsin card-sorting taskthe Wisconsin card-sorting task Object perObject permmanence anence

tasks:tasks:• Are Are mmastered by infants astered by infants

at the age of 7 or 8 at the age of 7 or 8 mmonthsonths

• Adult Adult mmonkeys with onkeys with prefrontal lesions prefrontal lesions respond like irespond like immmmature ature huhumman infantsan infants

© Bob Daemmrich/Stock, Boston

The Basal Ganglia and The Basal Ganglia and Procedural MemoryProcedural Memory

Lesions of the Lesions of the hippocampus hippocampus impaired declarative impaired declarative memories memories (remember where (remember where you went last time)you went last time)

Lesions of the Lesions of the caudate nucleus caudate nucleus (basal ganglia) (basal ganglia) impaired procedural impaired procedural memoriesmemories

Patients with Patients with Huntington’s Huntington’s disease and disease and Parkinson’s disease Parkinson’s disease have procedural have procedural memory deficits, memory deficits, but not declarative but not declarative memory deficitsmemory deficits

Genetic Manipulation of Genetic Manipulation of Learning AbilityLearning Ability

DrosophilaDrosophila can learn to avoid odors can learn to avoid odors associated with electric shockassociated with electric shock

Blocking the expression of the Protein Blocking the expression of the Protein Kinase A gene prevents learning and Kinase A gene prevents learning and formation of short-term memoriesformation of short-term memories

Too much CREB-2 blocks long but not Too much CREB-2 blocks long but not short-term memoriesshort-term memories

Extra CREB-1 produces immediate Extra CREB-1 produces immediate long-term memorylong-term memory

Unusual Memory PhenomenaUnusual Memory Phenomena RepressionRepression FlashbacksFlashbacks Flashbulb Flashbulb

memoriesmemories Stress affects the Stress affects the

amygdala and amygdala and hippocampus hippocampus

Cortisol may Cortisol may damage the damage the hippocampushippocampus

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Eye Witness TestimonyEye Witness Testimony Beth Loftus: False MemoriesBeth Loftus: False Memories Had students go home and ask younger Had students go home and ask younger

siblings: Hey, do you remember that siblings: Hey, do you remember that time when you got lost in the mall?time when you got lost in the mall?

The siblings had never been lost in the The siblings had never been lost in the mallmall

The siblings conjured up detailed storiesThe siblings conjured up detailed stories Bugs Bunny at DisneylandBugs Bunny at Disneyland

Memory and Normal AgingMemory and Normal Aging

In healthy adults, most measures of In healthy adults, most measures of cognitive ability remain stablecognitive ability remain stable

Memory loss may accompany changes Memory loss may accompany changes in brain systems that utilize the in brain systems that utilize the neurotransmitter acetylcholine (ACh)neurotransmitter acetylcholine (ACh)

Attaining an above-average education; Attaining an above-average education; engaging in complex, non-routine engaging in complex, non-routine professions; and earning high income professions; and earning high income appear to protect against cognitive appear to protect against cognitive declinedecline