memory - form and function

Memory and Its Mechanism

Chairperson

Dr. T. Kumanan MD., DPM, Professor

Dr. S. J. X. Sugadev MD., Assistant Professor

Slide 1

Presented byDr. A. M. Anusa

First Year PG

Prepared by Prof. Rooban T,

Oral & Maxillofacial Pathologist

Memory

Origin of word from Greek God - Mnemosyne

Slide 2

Introduction Neurobiology of memory

Identifying where and how different types of information are stored

Hypothesis by Hebb Memory results from synaptic

alterations Study of simple invertebrates

Synaptic alterations underlie memories (procedural)

Electrical stimulation of brain Experimentally produce measurable

synaptic alterations - dissect mechanisms

Slide 3

Procedural Learning Declarative and

procedural memories Nonassociative Learning

Habituation▪ Learning to ignore

stimulus that lacks meaning

Sensitization▪ Learning to intensify

response to stimuli

Slide 4

Procedural Learning

Associative Learning Classical Conditioning

Slide 5

Procedural Learning

Associative Learning (Cont’d) Classical Conditioning

▪ Associates a stimulus that evokes response- unconditional stimulus with second stimulus that does not evoke response- conditional stimulus

Instrumental Conditioning▪ Experiment by Edward Thorndike ▪ Complex neural circuits due to motivation

Slide 6

Simple Systems: Invertebrate Models of Learning

Experimental advantages in using invertebrate nervous systems Small nervous systems Large neurons Identifiable neurons Identifiable circuits Simple genetics

Slide 7


Nonassociative Learning in Aplysia

Slide 8


Nonassociative Learning in Aplysia (Cont’d) Habituation of the Gill-Withdrawal Reflex

Slide 9


Nonassociative Learning in Aplysia (Cont’d) Sensitization of the Gill-Withdrawal

Reflex

Slide 10


Associative Learning in Aplysia Classical

conditioning CS-US pairing

▪ Cellular level▪ Molecular level

Slide 11


The molecular basis for classical conditioning in Aplysia

Slide 12

Vertebrate Models of Learning

Neural basis of memory learned from invertebrate studies Learning and memory can result from

modifications of synaptic transmission Synaptic modifications can be triggered

by conversion of neural activity into intracellular second messengers

Memories can result from alterations in existing synaptic proteins

Slide 13


Synaptic Plasticity in the Cerebellar Cortex Cerebellum: Important site for motor

learning Anatomy of the Cerebellar Cortex

▪ Features of Purkinje cells▪ Dendrites extend only into molecular layer▪ Cell axons synapse on deep cerebellar nuclei

neurons▪ GABA as a neurotransmitter

Slide 14

Vertebrate Models of Learning The structure of the cerebellar cortex

Slide 15


Synaptic Plasticity in the Cerebellar Cortex Long-Term Depression in the Cerebellar

Cortex

Slide 16


Synaptic Plasticity in the Cerebellar Cortex (Cont’d) Long-Term Depression in the Cerebellar

Cortex (Cont’d)▪ Cerebellar LTD and Classical Conditioning in

Aplysia▪ Similarity: Input-specific synaptic modification ▪ Dissimilarity: Site of convergence and nature of

synaptic changes

Slide 17


Synaptic Plasticity in the Cerebellar Cortex (Cont’d) Mechanisms of cerebellar LTD

▪ Learning▪ Rise in [Ca2+]i and [Na+]i and the activation of protein

kinase C

▪ Memory▪ Internalized AMPA channels and depressed excitatory

postsynaptic currents

Slide 18


Synaptic Plasticity in the Hippocampus LTP and LTD

▪ Key to forming declarative memories in the brain

Bliss and Lomo▪ High frequency electrical stimulation of

excitatory pathway Anatomy of Hippocampus

▪ Brain slice preparation: Study of LTD and LTPSlide 19


Synaptic Plasticity in the Hippocampus (Cont’d) Anatomy of the Hippocampus

Slide 20


Synaptic Plasticity in the Hippocampus (Cont’d) Properties of LTP in CA1

Slide 21


Synaptic Plasticity in the Hippocampus (Cont’d) Mechanisms of LTP in

CA1▪ Glutamate receptors

mediate excitatory synaptic transmission▪ NMDARs and AMPARs

Slide 22


Synaptic Plasticity in the Hippocampus (Cont’d) Long-Term Depression in CA1

Slide 23


Synaptic Plasticity in the Hippocampus (Cont’d) BCM theory

▪ When the postsynaptic cell is weakly depolarized by other inputs: Active synapses undergo LTD instead of LTP

▪ Accounts for bidirectional synaptic changes (up or down)

Slide 24


Synaptic Plasticity in the Hippocampus (Cont’d) LTP, LTD, and Glutamate Receptor

Trafficking ▪ Stable synaptic transmission: AMPA receptors

are replaced maintaining the same number▪ LTD and LTP disrupt equilibrium▪ Bidirectional regulation of phosphorylation

Slide 25


LTP, LTD, and Glutamate Receptor Trafficking (Cont’d)

Slide 26



Slide 27


Synaptic Plasticity in the Hippocampus (Cont’d) LTP, LTD, and Memory

▪ Tonegawa, Silva, and colleagues▪ Genetic “knockout” mice▪ Consequences of genetic deletions (e.g., CaMK11 subunit)

▪ Advances (temporal and spatial control)▪ Limitations of using genetic mutants to study

LTP/learning: secondary consequences

Slide 28

The Molecular Basis of Long-Term Memory

Phosphorylation as a long term mechanism: Problematic (transient and turnover rates)

Persistently Active Protein Kinases Phosphorylation

maintained: Kinases stay “on” ▪ CaMKII and LTP

▪ Molecular switch hypothesis

Slide 29


Protein Synthesis Requirement of long-term memory

▪ Synthesis of new protein Protein Synthesis and Memory

Consolidation ▪ Protein synthesis inhibitors

▪ Deficits in learning and memory

CREB and Memory▪ CREB: Cyclic AMP response element binding

protein

Slide 30


Protein Synthesis (Cont’d) Structural Plasticity and Memory

▪ Long-term memory associated with formation of new synapses

▪ Rat in complex environment: Shows increase in number of neuron synapses by about 25%

Slide 31

Concluding Remarks

Learning and memory Occur at synapses

Unique features of Ca2+

Critical for neurotransmitter secretion and muscle contraction, every form of synaptic plasticity

Charge-carrying ion plus a potent second messenger▪ Can couple electrical activity with long-term

changes in brain Slide 32

End of Presentation

Slide 33

Cognitive ProcessesPSY 334Chapter 6 – Human

Memory: Encoding and Storage

Ebbinghaus

First rigorous investigation of human memory – 1885.

Taught himself nonsense syllables DAX, BUP, LOC

Savings – the amount of time needed to relearn a list after it has already been learned and forgotten.

Forgetting function – most forgetting takes place right away.

Memory Models

Atkinson & Shiffrin – proposed a three-stage model including: Sensory store – if attended goes to STM Short-term memory (STM) – if rehearsed

goes to LTM Long-term memory (LTM)

No longer the current view of memory. Still presented in some books.

The Three-Stage Model

Environment Sensory storeShort-term

(working) memory Long-term memory

Responses

Executive control processes

Sensation/perception Attention

encoding

retrieval

Retention Times

Environment Sensory storeShort-term

(working) memory Long-term memory

encoding

retrieval

1-3 seconds 15-25 seconds 1 sec to a lifetime

Sensory Memory

Holds info when it first comes in. Allows a person to extract meaning

from an image or series of sounds. Sperling’s partial report procedure:

A display of three rows of letters is presented.

After it is taken away, a tone signals which row to report.

Subjects were able to report most letters.

Sperling’s Partial Report

A medium tone signals the subject to report the letters in this row

Sperling’s Results

Delay

Kinds of Sensory Stores

Iconic memory – visual Bright postexposure field wipes out

memory after 1 sec, dark after 5 sec. Echoic memory – auditory

Lasts up to 10 sec (measured by ERP) Located in the sensory cortexes.

Short Term Memory

The original idea is that when info in sensory memory is paid attention to, it moves into short term memory.

With rehearsal, it then moves into long term memory.

STM has limited capacity, called memory span. Miller’s magic number (7 ± 2) New info pushes out older info

(Shepard)

Shepard’s Results

Number of intervening items

Probability of recalling the target item

Criticisms of STM

Rate of forgetting seemed to be quicker than Ebbinghaus’s data, but is not really.

Amount of rehearsal appeared to be related to transfer to long-term memory. Later it was found that the kind of

rehearsal matters, not the amount. Passive rehearsal does little to achieve

long-term memory. Information may go directly to LTM.

Depth of Processing

Craik & Lockhart – proposed that it is not how long material is rehearsed but the depth of processing that matters.

Levels of processing demo.

Working Memory

Baddeley – in working memory speed of rehearsal determines memory span. Articulatory loop – stores whatever can be processed in a given amount of time. Word length effect: 4.5 one-syllable

words remembered compared to 2.6 long ones.

1.5 to 2 seconds material can be kept. Visuopatial sketchpad – rehearses

images. Central executive – controls other

systems.

Word-Lenth Determines Forgetting

Delayed Matching Task

Delayed Matching to Sample – monkey must recall where food was placed. Monkeys with lesion to frontal cortex

cannot remember food location. Human infants can’t do it until 1 year

old. Regions of frontal cortex fire only

during the delay – keeping location in mind. Different prefrontal regions are used to

remember different kinds of information.

Delayed Matching to Sample

Importance of Frontal Cortex

In primates, working memory is localized to the frontal cortex.

Delayed matching to sample task: Monkeys are shown food that is then

hidden. Later they are given a chance to locate

it. Monkeys with frontal lobe lesions

cannot do this task.

Activation

Activation – how available information is to memory: Probability of access – how likely you are

to remember something. Rate of access – how fast something can

be remembered. From moment to moment, items

differ in their degree of activation in memory.

Anderson’s ACT Model

ACT – Adaptive Control of Thought Moses Effect -- subjects shown the

words Bible, animal and flood should recall Noah but recall Moses instead. When given the word flood they think of

Mississippi or Johnstown but not Noah. Why? Recall is based on both

baseline and activation from associated concepts. Moses and Jesus have higher baselines.

The ACT Model

Factors Affecting Activation

How recently we have used the memory: Loftus – manipulated amount of delay 1.53 sec first time, then 1.21, 1.28, and

1.33 with 3 items intervening. How much we have practiced the

memory – how frequently it is used. Anderson’s study (sailor is in the park)

Spreading Activation

Activation spreads along the paths of a propositional network. Related items are faster to recall.

Associative priming – involuntary spread of activation to associated items in memory. Kaplan’s dissertation – cues to solving

riddles hidden in the environment led to faster solutions.

Associative Priming

Meyer & Schvaneveldt – spreading activation affects how quickly words are read. Subjects judged whether pairs of related

& unrelated items were words. Judgments about related words were

faster.

Meyer and Schvaneveldt

Practice and Strength

The amount of spreading activation depends on the strength of a memory.

Memory strength increases with practice.

Greater memory strength increases the likelihood of recall.

Power Function

Each time we use a memory trace, it gradually becomes a little stronger.

Power law of learning: T = 1.40 P-0.24

T is recognition time, P is days of practice.

Linear when plotted on log-log scale.

Learning Curves

Practicing Addition Problems

Long Term Potentiation (LTP)

Neural changes may occur with practice: Long-term potentiation (LTP) in

hippocampus. Repeated electrical stimulation of

neurons leads to increased sensitivity. LTP changes are a power function.

Neural Changes Mirror Behavioral Changes

Neural Correlates of Encoding

Better memory occurs for items with stronger brain processing at the time of study: Words evoking higher ERP signals are

better remembered later. Greater frontal activation with deeper

processing of verbal information. Greater activation of hippocampus with

better long-term memory.

Activation in Prefrontal Cortex

Words activate left prefrontal cortex

Pictures activate right prefrontal cortex

Hemodynamic = blow flow during brain activity

Factors Influencing Memory

Study alone does not improve memory – what matters is how studying is done. Shallow study results in little

improvement. Semantic associates (tulip-flower) better

remembered than rhymes (tower-flower), 81% vs 70%.

Better retention occurs for more meaningful elaboration.

Elaborative Processing

Elaboration – embellishing an item with additional information.

Anderson & Bower – subjects added details to simple sentences: 57% recall without elaboration 72% recall with made-up details added

Self-generated elaborations are better than experimenter-generated ones.

Self-Generated Elaborations

Stein & Bransford – subjects were given 10 sentences. Four conditions: Just the sentences alone – 4.2 adjectives Subject generates an elaboration – 5.8 Experimenter-generated imprecise

elaboration – 2.2 Experimenter-generated precise

elaboration – 7.8 Precision of detail (constraint)

matters, not who generates the elaboration.

Advance Organizers

PQ4R method – use questions to guide reading. 64% correct, compared to 57% (controls) 76% of relevant questions correct, 52%

of non-relevant. These study techniques work

because they encourage elaboration. Question making and question

answering both improve memory for text (reviewing is better than seeing the questions first).

Meaningful Elaboration

Elaboration need not be meaningful – other sorts of elaboration also work.

Kolers compared memory for right-side-up sentences with upside-down. Extra processing needed to read upside

down may enhance memory. Slamecka & Graf – compared

generation of synonyms and rhymes. Both improved memory, but synonyms did more.

Slamecka & Graf’s Results

Mnemonics

Method of Loci – place items in a location, then take a mental walk.

Peg-word System – use peg words as a structure and associate a list of items with them using visualization. Create acronyms for lists of items.

Convert nonsense syllables (DAX, GIB) into meaningful items by associating them with real words (e.g., DAD).

“This Old Man” Song

http://www.youtube.com/watch?v=3cYf9vkW_xU

http://www.totlol.com/watch/5d-6Q5V79CM/This-Old-Man/0/

http://www.youtube.com/watch?v=3cYf9vkW_xU

http://www.totlol.com/watch/5d-6Q5V79CM/This-Old-Man/0/

Pegword System

1 – bun2 – shoe3 – tree4 – door5 – hive6 – sticks7 – heaven8 – gate9 – wine10 -- hen

Incidental Learning

It does not matter whether people intend to learn something or not. What matters is how material is

processed. Orienting tasks:

Count whether work has e or g. Rate the pleasantness of words. Half of subjects told they would be asked

to remember words later, half not told. No advantage to knowing ahead of

time.

Awareness of Learning

Flashbulb Memories

Self-reference effect -- people have better memory for events that are important to them and close friends.

Flashbulb memories – recall of traumatic events long after the fact. Seem vivid but can be very inaccurate.

Thatcher’s resignation: 60% memory for UK subjects, 20% non-

UK

Self-Reference Effect

Two explanations: People have special mechanisms for

encoding info relevant to themselves. Info relevant to the self is rehearsed

more often. High arousal may enhance memory. Memory is better for words related to

the self – perhaps due to better elaboration.

PSYCHOLOGY 110-02General Psychology

University of Southern Mississippi Department of Psychology

Dr. David J. Echevarria, PhD Spring 2008

[email protected] www.usm.edu/neurolab

Chapter 7 Memory

mailto:[email protected]

Chapter 7: Human Memory

Minute quiz…

Chapter 6 is on learningChapter 7 is on memory

How is memory related to learning???

Without memory learning is useless!

Think about all the times in one day you rely on your memory:

When is my next class? Did I pay my rent? Where did I park my car? When is my boy/girl friend’s

birthday? Performance on exams

How are memories stored?

Tip of the tongue

Did you ever say, “I can’t remember” only to actually “remember” later on?

How easily are they accessed?

What can interfere with memory?

What’s the capacity of short-term memory?

Memory span: Number of items that can be recalled from short-term memory, in order, on half of the tested memory trials It’s about 7 plus or minus 2 items

Not absolute; also depends on: How quickly items can be rehearsed Chunking

▪ Rearranging incoming information into meaningful or familiar patterns

The Working Memory Model Several distinct mechanisms:

Phonological loop: Like the inner voice; stores word sounds

Visuospatial sketchpad: Stores visual and spatial information

Central executive: Determines which mechanism to use, coordinates among them

Brain damage can selectively affect a single mechanism

Human Memory: Basic Questions

How does information get into memory? How is information maintained in

memory? How is information pulled back out of

memory?

Figure 7.2 Three key processes in memory

Encoding: Getting Information Into Memory

The role of attention Focusing awareness Selective attention = selection of input

Filtering: early or late?

Figure 7.3 Models of selective attention

Levels of Processing:Craik and Lockhart (1972)

Incoming information processed at different levels

Deeper processing = longer lasting memory codes

Encoding levels: Structural = shallow Phonemic = intermediate Semantic = deep

Figure 7.4 Levels-of-processing theory

Above is a scanpath of one reader over a broadsheet newspaper spread. The reader turned pages in her own pace, and read the entire newspaper. This is quite typical data. The texts are read no deeper than 40 % of their lengths. Very short looks on photos and long looks on information graphics.

http://www.sol.lu.se/humlab/eyetracking/

Scanning a Scene

Figure 7.5 Retention at three levels of processing

Enriching Encoding: Improving Memory

Elaboration = linking a stimulus to other information at the time of encoding Thinking of examples

Visual Imagery = creation of visual images to represent words to be remembered Easier for concrete objects: Dual-coding

theory Self-Referent Encoding

Making information personally meaningful

Storage: Maintaining Information in Memory

Analogy: information storage in computers ~ information storage in human memory

Information-processing theories Subdivide memory into 3 different stores

▪ Sensory, Short-term, Long-term

Figure 7.7 The Atkinson and Schiffrin model of memory storage

Sensory Memory

Brief preservation of information in original sensory form

Auditory/Visual – approximately ¼ second George Sperling (1960)

▪ Classic experiment on visual sensory store

Figure 7.8 Sperling’s (1960) study of sensory memory

Short Term Memory (STM)

Limited capacity – magical number 7 plus or minus 2 Chunking – grouping familiar stimuli

for storage as a single unitLimited duration – about 20

seconds without rehearsal Rehearsal – the process of repetitively

verbalizing or thinking about the information

Figure 7.9 Peterson and Peterson’s (1959) study of short-term memory

Short-Term Memory as “Working Memory”

STM not limited to phonemic encoding Loss of information not only due to

decay Baddeley (1986) – 3 components of

working memory Phonological rehearsal loop Visuospatial sketchpad Executive control system

Long-Term Memory: Unlimited Capacity

Permanent storage? Flashbulb memories Recall through hypnosis

Debate: are STM and LTM really different? Phonemic vs. Semantic encoding Decay vs. Interference based

forgetting

How is Knowledge Representedand Organized in Memory?

Clustering and Conceptual Hierarchies Schemas and Scripts Semantic Networks Connectionist Networks and PDP Models

Retrieval: Getting InformationOut of Memory

The tip-of-the-tongue phenomenon – a failure in retrieval Retrieval cues

Recalling an event Context cues

Reconstructing memories Misinformation effect

▪ Source monitoring, reality monitoring

Forgetting: When Memory Lapses

Retention – the proportion of material retained Recall Recognition Relearning

Ebbinghaus’s Forgetting Curve

Figure 7.16 Ebbinghaus’ forgetting curve for nonsense syllables

Figure 7.17 Recognition versus recall in the measurement of retention

Why Do We Forget?

Ineffective EncodingDecay theory Interference theory

Proactive Retroactive

Figure 7.19 Retroactive and proactive interference

Figure 7.20 Estimates of the prevalence of childhood physical and sexual abuse

Retrieval Failure

Encoding Specificity Transfer-Appropriate Processing Repression

Authenticity of repressed memories? Memory illusions Controversy

Figure 7.22 The prevalence of false memories observed by Roediger and McDermott (1995)

The Physiology of Memory

Biochemistry Alteration in synaptic transmission

▪ Hormones modulating neurotransmitter systems

▪ Protein synthesisNeural circuitry

Localized neural circuits▪ Reusable pathways in the brain▪ Long-term potentiation

The Physiology of Memory

Anatomy Anterograde and Retrograde Amnesia

▪ Cerebral cortex, Prefrontal cortex, Hippocampus,

▪ Dentate gyrus, Amygdala, Cerebellum

Figure 7.23 The anatomy of memory

Figure 7.25 Retrograde versus anterograde amnesia

Are There Multiple Memory Systems?

Declarative vs. Procedural Semantic vs. Episodic Prospective vs. Retrospective

Figure 7.26 Theories of independent memory systems

Improving Everyday Memory

Engage in adequate rehearsal Distribute practice and minimize

interference Emphasize deep processing and

transfer-appropriate processing Organize information Use verbal mnemonics Use visual mnemonics

Neuroscience: Exploring the Brain, 3e

Chapter 25: Molecular Mechanisms of Learning and Memory

Introduction

Neurobiology of memory Identifying where and how different types

of information are stored Hebb

Memory results from synaptic modification Study of simple invertebrates

Synaptic alterations underlie memories (procedural)

Electrical stimulation of brain Experimentally produce measurable

synaptic alterations - dissect mechanisms

Procedural Learning

Procedural memories amenable to investigation

Nonassociative Learning Habituation

▪ Learning to ignore stimulus that lacks meaning

Sensitization▪ Learning to intensify

response to stimuli

Procedural Learning Associative Learning

Classical Conditioning: Pair an unconditional stimulus (UC) with a conditional stimulus (CS) to get a conditioned response (CR)

Procedural Learning Associative Learning (Cont’d)

Instrumental Conditioning▪ Learn to associate a response with a

meaningful stimulus, e.g., reward lever pressing for food

▪ Complex neural circuits related to role played by motivation


Experimental advantages in using invertebrate nervous systems Small nervous systems Large neurons Identifiable neurons Identifiable circuits Simple genetics


Nonassociative Learning in Aplysia Gill-withdrawal reflex Habituation


Nonassociative Learning in Aplysia (Cont’d) Habituation results from presynaptic modification at L7


Nonassociative Learning in Aplysia (Cont’d) Repeated electrical stimulation of a sensory neuron leads to

a progressively smaller EPSP in the postsynaptic motor neuron


Nonassociative Learning in Aplysia (Cont’d) Sensitization of the Gill-Withdrawal Reflex involves L29

axoaxonic synapse


Nonassociative Learning in Aplysia (Cont’d) 5-HT released by L29 in

response to head shock leads to G-protein coupled activation of adenylyl cyclase in sensory axon terminal.

Cyclic AMP production activates protein kinase A.

Phosphate groups attach to a potassium channel, causing it to close


Nonassociative Learning in Aplysia (Cont’d) Effect of decreased

potassium conductance in sensory axon terminal

More calcium ions admitted into terminal and more transmitter release


Associative Learning in Aplysia Classical conditioning: CS

initially produces no response but after pairing with US, causes withdrawal


• The molecular basis for classical conditioning in Aplysia– Pairing CS and US causes greater activation of adenylyl cyclase

because CS admits Ca2+ into the presynaptic terminal

Vertebrate Models of Learning Neural basis of memory: principles

learned from invertebrate studies Learning and memory can result from

modifications of synaptic transmission Synaptic modifications can be triggered

by conversion of neural activity into intracellular second messengers

Memories can result from alterations in existing synaptic proteins

Vertebrate Models of Learning Synaptic Plasticity in the Cerebellar

Cortex Cerebellum: Important site for motor

learning Anatomy of the Cerebellar Cortex

▪ Features of Purkinje cells▪ Dendrites extend only into molecular layer▪ Cell axons synapse on deep cerebellar nuclei

neurons▪ GABA as a neurotransmitter

Vertebrate Models of Learning The structure of the cerebellar cortex


• Cancellation of expected reafference in the electrosensory cerebellum of skates- synaptic plasticity at parallel fiber synapses.


Synaptic Plasticity in the Cerebellar Cortex Long-Term Depression in the Cerebellar

Cortex

Vertebrate Models of Learning Synaptic Plasticity in the Cerebellar

Cortex (Cont’d) Mechanisms of cerebellar LTD

▪ Learning▪ Rise in [Ca2+]i and [Na+]i and the activation of protein

kinase C

▪ Memory▪ Internalized AMPA channels and depressed excitatory

postsynaptic currents


Synaptic Plasticity in the Cerebellar Cortex (Cont’d)

Vertebrate Models of Learning Synaptic Plasticity in the Hippocampus

LTP and LTD▪ Key to forming declarative memories in the brain

Bliss and Lomo▪ High frequency electrical stimulation of excitatory

pathway Anatomy of Hippocampus

▪ Brain slice preparation: Study of LTD and LTP


Synaptic Plasticity in the Hippocampus (Cont’d) Anatomy of the Hippocampus


Synaptic Plasticity in the Hippocampus (Cont’d) Properties of LTP in CA1


Synaptic Plasticity in the Hippocampus (Cont’d) Mechanisms of LTP in CA1

▪ Glutamate receptors mediate excitatory synaptic transmission▪ NMDA receptors and

AMPA receptors


Synaptic Plasticity in the Hippocampus (Cont’d) Long-Term Depression in CA1


Synaptic Plasticity in the Hippocampus (Cont’d) BCM theory

▪ When the postsynaptic cell is weakly depolarized by other inputs: Active synapses undergo LTD instead of LTP

▪ Accounts for bidirectional synaptic changes (up or down)

Vertebrate Models of Learning Synaptic Plasticity in the

Hippocampus (Cont’d) LTP, LTD, and Glutamate Receptor

Trafficking ▪ Stable synaptic transmission: AMPA receptors

are replaced maintaining the same number▪ LTD and LTP disrupt equilibrium▪ Bidirectional regulation of phosphorylation

Vertebrate Models of Learning LTP, LTD, and Glutamate Receptor

Trafficking (Cont’d)

Vertebrate Models of Learning Synaptic Plasticity in the Hippocampus (Cont’d)

LTP, LTD, and Memory▪ Tonegawa, Silva, and colleagues

▪ Genetic “knockout” mice▪ Consequences of genetic deletions (e.g., CaMK11

subunit)▪ Advances (temporal and spatial control)

▪ Limitations of using genetic mutants to study LTP/learning: secondary consequences


Phosphorylation as a long term mechanism:Persistently Active Protein Kinases Phosphorylation maintained:

Kinases stay “on” ▪ CaMKII and LTP

▪ Molecular switch hypothesis


Protein Synthesis Protein synthesis required for formation of

long-term memory▪ Protein synthesis inhibitors

▪ Deficits in learning and memory

CREB and Memory▪ CREB: Cyclic AMP response element binding

protein

The Molecular Basis of Long-Term Memory Protein Synthesis (Cont’d)

Structural Plasticity and Memory▪ Long-term memory associated with

transcription and formation of new synapses▪ Rat in complex environment: Shows increase

in number of neuron synapses by about 25%

Concluding Remarks Learning and memory

Occur at synapses Unique features of Ca2+

Critical for neurotransmitter secretion and muscle contraction, every form of synaptic plasticity

Charge-carrying ion plus a potent second messenger▪ Can couple electrical activity with long-term

changes in brain

End of Presentation


The molecular basis for classical conditioning in Aplysia Pairing CS and US causes greater activation of

adenylyl cyclase because CS admits Ca2+ into the presynaptic terminal


Associative Learning in Aplysia Classical conditioning: CS initially produces no response

but after pairing with US, causes withdrawal


Synaptic Plasticity in Human area IT

LECTURE 20-21: CELLULAR BASIS OF LEARNING & MEMORY

REQUIRED READING: Kandel text, Chapter 63, and Assigned Review Articles

Research on cellular basis of learning & memory mainly performed in three animal systems

Aplysia Drosophila Mouse

All neurons and synapsesin behavioral circuits areidentified and can be recorded easily

Ideal for detailing mechanisms underlying implicit learned motor responses

Capable of learned behaviors

Amenable to randommutagenesis andselection of mutantswith defectivebehaviors

Similar anatomy to human

Amenable to study ofexplicit memory

Hippocampus amenableto electrophysiology

Behavior modification ofgenetically modified mice

APLYSIA SHORT-TERM LEARNED RESPONSES AFFECTING GILL WITHDRAWL REFLEX

HABITUATION SENSITIZATION CLASSICALCONDITIONING

Repeated tactile stimulation of siphon depressesgill withdrawl response

Harmful stimulussensitizesgill withdrawl responseto subsequentharmful OR harmlessstimuli given tosame OR differentbody regions

Pairing harmful stimuluswith preceding harmless conditioning stimulus sensitizesgill withdrawl responseto subsequentconditioning stimulusbut not to tactile stimuligiven to other body areas

HABITUATION IS DUE TO DEPRESSED NEUROTRANSMITTER RELEASE AT SEVERAL SITES

Rapidly repeated tactile stimulation of siphonattenuates gill withdrawl both during thetraining and for a short period afterwards.

Habituation is due to reducedneurotransmitter release by thesensory neuron and by relevant interneuronsin response to the tactile stimulus.I.e., the memory of habituationis distributed at various synapsesin the circuit

Whereas a rapid series of stimuli inducesshort-term habituation,several sets of tactile stimuli distributedover several hours induceslong-term habituation that lasts for weeks.

Long-term habituation requiresnew protein synthesis and is due to pruning of synaptic connections

SHORT-TERM SENSITIZATION IS MEDIATED THROUGH AXO-AXONICSEROTONERGIC SYNAPSES OF FACILITATING INTERNEURONS

Serotonergic facilitating interneuronssend axo-axonic connections tobroadly distributed sensory neurons

Unconditioned stimulus causes interneurons to release serotonin,which acts through metabotropicHT receptors to increase thelikelihood of neurotransmitter releasefollowing sensory neuron firing

Sensitization can be mimicked withoutsensitizing stimulus by local experimental application of serotonin

Sensitization is mediated bypresynaptic elevation of cAMP & PKA activity,which has three effects:

1) Greater proportion of vesicles in active zone(synapsin phosphorylation?)

2) K+ channel inactivation increases duration of depolarization andmagnitude of Ca+2 influx

3) Activation of L--type calcium channels

CLASSICAL CONDITIONING EMPLOYS SEQUENCE-REINFORCED PRODUCTION OF cAMP

Conditioning is only effective when CS precedes US by a short interval (~ 0.5 sec)

CS elevates calcium in presynaptic terminal at moment of US.Calcium/CAM enhances the enzymatic activity of adenylate cyclase triggered by 5-HT.

Adenylate cyclase is a biochemical “coincidence detector”

TEMPORALLY SPACED SENSITIZATION OR CONDITIONING TRAININGSINDUCE LONG-TERM IMPLICIT MEMORY

Long-term sensitization

and conditioning arealso mediated through presynaptic cAMP

productionand PKA activity

PKA induces specific CREB-dependentgene transcription and protein synthesis:

Newly synthesized ubiquitin

hydrolase degrades PKA regulatory

subunits, making the enzymeconstitutively active

Other newly synthesized

proteins help build new

presynaptic terminalsonto motor neurons

GENETIC SCREENS FOR GENES AFFECTING CONDITIONING IMPLICIT MEMORYALL AFFECT THE cAMP-PKA-CREB PATHWAY

FLY MUTANTS SELECTED FOR DEFECTS IN IMPLICIT MEMORY

DUNCE encodes cAMP phosphodiesterase

RUTABAGA mutant defective for Ca+2/CAM enhancement of cyclase

AMNESIAC encodes a peptide neurotransmitter acting on GS-coupled receptor

PKA-R1 encodes PKA

HIPPOCAMPAL NEURONS IN DIFFERENT RELAYS ARE ALLCAPABLE OF UNDERGOING SYNAPTIC LONG-TERM POTENTIATION

AXON STIMULATION PROTOCOL AMPLITUDE OF EPSCS

20 min1 m 60 minOnce

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100

200

TIME (min)6020 40 80“THETA” BURST

One Theta burst gives what is sometimes calledEarly LTP, which is less than doublingof EPSC which lasts for hours

Four Theta bursts spaced minutes apart generateLate LTP, with up to 4-fold EPSC stimulationthat lasts for days

INDUCTION AND EXPRESSION OF SYNAPTIC PLASTICITY

Prior synaptic activity can INDUCE long-term plasticity. Such plasticity can be INDUCED by molecular events occuring either presynaptically or postsynaptically.

The changes in transmission following synaptic plasticity can be EXPRESSED either presynaptically and/or postsynaptically, and need not correspond to the site of INDUCTION.

E.g., at a certain synapse, postsynaptic calcium influx can INDUCE plasticity which is then EXPRESSED as changes in presynaptic neurotransmitter release probability.

LTP AT MOSSY FIBER--CA3 SYNAPSES IS DUE TO PRESYNAPTIC CALCIUM INFLUXAND cAMP/PKA PATHWAY

LTP AT SCHAFFER COLLATERAL--CA1 SYNAPSES IS DUE TO POSTSYNAPTIC CALCIUM INFLUX AND CAM KINASE ACTIVITY

LTP at CA3-CA1 synapse is blocked byNMDAR antagonist APV and by inhibitorsof CAM kinase

PRESYNAPTIC COMPONENT OF EARLY AND LATE LTP AT CA3--CA1 SYNAPSES RESEMBLES SHORT- AND LONG-TERM SENSITIZATION

Late LTPabsolutely requiresnew protein synthesis

PRESYNAPTIC COMPONENT OF EARLY AND LATE LTP REQUIRES POSTSYNAPTIC CAMK ACTIVITY AND RETROGRADE SIGNALS

OTHER MECHANISMS OF PLASTICITY ENHANCING EPSPS

LTP can be expressed postsynaptically as a reduction of leak conductance in dendritic spine. This enables the EPSC to generate EPSP with greater length and time constants.

Excitatory transmission can be enhanced by HETEROSYNAPTIC INHIBITION OF INHIBITORY TRANSMISSION. This is mediated by endogenous cannabinoids acting on presynpatic terminals of nearby GABAergic synapses.

IS LTP REQUIRED FOR HIPPOCAMPAL CONSOLIDATION OF EXPLICIT MEMORY?CAMK AND NMDAR1 NEEDED FOR LONG-TERM SPATIAL REPRESENTATION IN HIPPOCAMPUS

Single pyramidal neuronin hippocampusfires when mouse is incertain location(independent ofanimal’s orientation)

Normal mouse remembers where it has been.spatial map in HCdoes not change insubsequent chamber trials

Mice with hippocampus-restricted mutationsin CAMK or NMDAR1establish place fields,but do not rememberfrom day to day

IS LTP REQUIRED FOR HIPPOCAMPAL CONSOLIDATION OF EXPLICIT MEMORY?HIPPOCAMPAL CAMK AND NMDAR1 NEEDED FOR BOTH LTP AND SPATIAL MEMORY

SYNAPSES SENSITIVE TO NMDAR-MEDIATED LTP ARE ALSO SENSITIVETO NMDAR-MEDIATED LONG-TERM DEPRESSION (LTD)

AXON STIMULATION PROTOCOL AMPLITUDE OF EPSCS


per

min

ute

Once p

er m

inute

10 Hz

EP

SP

Slo

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(% o

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300

100

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TIME (min)6020 40 80

LTP


per

min

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Once p

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2 Hz

EP

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100

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TIME (min)6020 40 80

LTD

LTD HAS A LOWER CALCIUM CONCENTRATION THRESHOLD THAN LTP,BUT LTP IS DOMINANT

LOW-FREQUENCY STIMULUS TRAIN

LOW-LEVEL CALCIUM ENTRY

ACTIVATION OF CALCINEURIN

AMPA RECEPTOR INTERNALIZATION

LTD

THETA- OR HIGH-FREQUENCY STIMULUS TRAIN

GREATER CALCIUM ENTRY

ACTIVATION OF CALCINEURIN AND CAMK

AMPA RECEPTOR INSERTION AND PHOSPHORYLATION

LTP

STRUCTURAL AND FUNCTIONAL FEATURES OF AMPA-TYPE GLUTAMATE RECEPTORS

AMPA receptors are homo- or hetero-tetramersRestriction of calcium entry mediated by GluR2; tetramers containing >1 GluR2 subunit conduct only Na+/K+

AMPA receptors encoded by different genes or by alternative splicing have different C-terminal tails.Receptor tails contain phosphorylation sites for different protein kinases and binding sitesfor PDZ-domain-containing proteins

Receptors containing only GluR2(short) and/or GluR3 subunits are delivered constitutively fromvesicles to synapseRetention at synapse mediated by complex with Glutamate Receptor Interacting Protein (GRIP)

Receptors containing at least one GluR1(long) subunit are stored in intracellular vesicles near synapseDuring LTP, GluR1-containing tetramers are added to the synapse

NMDAR-INDUCED CAMK ACTIVITY ACTS ON AMPA RECEPTORS IN TWO WAYSTO PROMOTE LTP

CAMKPDZ-protein

STGGRIPPSD-95

GRIPPSD-95

Calcineurin

CAMK phosphorylates an unknownprotein, enabling a PDZ-proteinthat interacts with long tailon GluR1 to deliver receptorTO EXTRASYNAPTIC SITE

Delivered receptors migrate (randomly?)into post-synaptic density,where interactions of receptor-associated GRIP and STG and themajor postsynaptic matrix proteinPSD-95 anchor receptor to synapse

Newly delivered GluR1-containingAMPA receptors can be phosphorylateddirectly by CAMK, whichincreases unitary conductanceof the receptor

Calcineurin activation promotes internalizationof AMPA receptors containing onlyshort-tail subunits, thereby promoting LTD

WHEN HIGH CALCIUM ENTRY ACTIVATES BOTH CALCINEURIN AND CAMK,CAMK-MEDIATED GluR1-CONTAINING AMPAR EXOCYTOSIS EXCEEDS CALCINEURIN-MEDIATEDSHORT TAIL-ONLY AMPAR ENDOCYTOSIS

HIGH CAMK ACTIVITY INDUCED DURING LATE LTP IS ALSO MEDIATED BYNEW CAM KINASE PROTEIN SYNTHESIS NEAR THE SYNAPSE

Most mRNAs have 3’ polyA tail, which is necessary for initiation of the mRNA’s translation

Neurons contain some mRNAs that are not polyadenylated, are not translated,and are transported along dendrites to areas near dendritic spines

NMDA receptor activation and calcium entry activates a protein kinasecalled AURORA

Aurora kinase activates translation of nearby dormant mRNAs

ONE OF THESE DORMANT RNAs ENCODES CAM KINASE

Because of its dendritic localizaation, new CAMK synthesis is restricted to the synapse undergoing LTP

The dendritic localization of dormant CAMK RNA and its activation during LTP are mediated byCytoplasmic Polyadenylation Element Binding (CPEB) protein

HOW DOES CPEB PROTEIN CONTROL RNA DORMANCY AND ACTIVATION IN NEURONS?

PolyA is needed for assembly of 5’translation initiation complex

CPEB protein binding to 3’ CPEhelps mask RNA 5’ end

CPEB phosphorylation by Aurora allows for recruitment of polyA polyermerase (PAP)

Polyadenylation of dormant RNA allows assembly of 5’ translation initiation complex

Memory DisordersPsychology 3717

Introduction

The strange case of Charles D’Sousa

Or is it Philip Cutajar?

Rare type of disorder

Some stuff clearly spared

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Introduction

Results with amnesiacs has lead to many discoveries about memory Episodic vs. semantic memory Procedural vs. declarative memory Implicit vs. explicit memory Phonological loop vs. visuo spatial

sketchpad

problems

Taxonomy Individual differences Interpretation Application Mostly comes down to a lack of

control, which of course is inevitable

Case studies

We pretty much have to rely on these

They are, thankfully, rare Usually some sort of accident or a

stroke

Case SP

Stroke patient Both Medial temporal lobes, left Hp

and lots of surrounding area, but not the amygdala

Had trouble naming objects Anterograde and retrograde amnesia Similar to KC

Clive Wearing

Case of encephalitis Pervasive amnesia Both semantic and

episodic impairment Temporal lobe

dilation Hp destroyed

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Performance Patterns

Retrograde amnesia Losing past memories

Anterograde amnesia No new memories

Spared function Often implicit tasks, such as priming or

ability to learn a new skill

Typically spared

Working Memory Semantic memory

Even KC could learn new stuff Declarative information using

Tulving’s method Restrict errors

Why?

Difficulties in interference, retrieval and encoding

Consolidation Tends to come down to something to do

with HP Context or sending item off for

processing or some such thing

Semantic memory problems

What is a cat? Temporal lobe problems Oddly enough, episodic memory

often intact in these rare cases

Working Memory Problems

There are cases of people with intact phonological loops and visuo spatial sketchpads that are pretty much toast

And vice versa

Alzheimer’s More than half of all

dementia is from AD 2 times more

women than men Could be because

women live longer though

dementia and brain stuff Neurofibrillary tangles

and neuritic plaques

AD

MASSIVE cell death In essence, you get like lesions

everywhere ‘cortical’ dementia, but you get

these lesions, holes really, everywhere

Neurotransmitters affected

ACh is important in memory, especially in HP

The ACh system is severely damaged in AD

Indeed it is almost targeted Other systems too though

Memory effects

Episodic effects Eventually semantic effects Retrieval cues don’t help

Information was not even encoded Nondeclarative stuff, skills etc, are

the last to go

Treatment

Most drugs target the cholinergic system

This disease not only affects the victim, but also his/her family

NGF is promising Treatments will come, but, reversal, I

dunno Respite care is key for the family

Conclusions

Frankly there is not a great deal of hope for most amnesiacs

That said, neuroscience is moving pretty fast

Has helped us understand normal function

The information-processing model of human memory

Relations between iconic memory, short-term memory and long-term memory

Logie’s (1995) drawing of the components of working memory

Source: Adapted from Logie, R., Visual Spatial Working Memory, p. 127. © 1995. Reprinted by permission of Psychology Press Limited, Hove, UK.

The articulatory loop

The limits of short-term and working memory

Source: (a) Adapted from Peterson, L.M. and Peterson, J.M., Short-term retention of individual verbal items. Journal of Experimental Psychology, 1959, 58, 193–198., (b) Adapted from Waugh, N.C. and Norman, D.A., Primary memory. Psychological Review, 1965, 72, 89–104.

Shallow versus deep processing

Source: Based on Craik, F.I.M. and Lockhart, R.S., Levels of processing: A framework for memory research. Journal of Verbal Behavior, 1972, 11, 671–684.

Explicit versus implicit memory

Source: Based on data from Graf, P. and Mandler, G., Activation makes words more accessible, but not necessarily more retrievable. Journal of Verbal Learning and Verbal Behavior, 1984, 23, 553–568.

The Stroop effect

Ebbinghaus’s forgetting curve

Source: Adapted from Ebbinghaus, H., Memory: A contribution to experimental psychology (H.A. Ruger and C.E. Bussenius, trans.), 1885/1913. Teacher’s College Press, Columbia University, New York.

Eyewitness testimony

Source: Based on data from Loftus, E.F. and Palmer, J.C., Reconstruction of automobile destruction: An example of the interaction between language and memory. Journal of Verbal Learning and Verbal Behavior, 1974, 13, 585–589.

Retroactive and proactive interference

Explicit and implicit memory of amnesic and non-amnesic individuals

Source: Adapted from Graf, P., Squire, L.R. and Mandler, G., The information that amnesic patients do not forget. Journal of Experimental Psychology: Learning, memory and cognition, 1984, 10, 164–178.

The effect of hippocampal damage on a

rat’s navigational ability

Source: Morris, R.G.M. et al., Place navigation impaired in rats with hippocampal lesions. Nature, 1982, 182(297), 681–683. Reprinted with permission from Nature. © 1982 Macmillan Magazines Limited.

Spatial navigation

Source: Maguire, E.A., Frackowiak, R.S.J. and Frith, C.D., Recalling routes around London: Activation of the right hippocampus in taxi drivers. Journal of Neuroscience, 1997, 17, 7103. © Society for Neuroscience.

Chapter 6:How Does Memory Function?

The Memory Process

Encode information into memory traces (stored bits of memory)

Process information and put into memory storage

Use retrieval to recall and output information when needed

Are Human Brains Like Computers?

• Information-processing approach: mind functions like a sophisticated computer

• Unlike computers, human minds have the capacity for consciousness ▪ Awareness of one’s own thoughts and

the external world▪ Focusing attention brings stimulus into

consciousness

Explicit and Implicit Memory

Explicit memory Conscious use of memory Searching memory for stored

information Implicit memory

Access and retrieve memories without conscious effort

The Traditional Three Stages Model of Memory

Sensory memory Information comes into sensory organs,

stored briefly in sensory form Short-term memory

Temporary holding tank for limited amounts of information

Long-term memory Permanent storage of memories

Sensory Memory: Iconic and Echoic Memory

Information received from sense organs lasts for short period of time

Acquire information primarily from sight (iconic memory) and hearing (echoic memory), but also through other senses (haptic memory)

Transfer occurs when we pay attention to sensory input to move it from iconic memory to short-term memory

Short-Term Memory: Where Memories Are Made (and Lost)

Temporary holding tank Utilizes dual-coding system

Memories stored visually or acoustically Limited capacity and duration

The Capacity of Short-term Memory: Seven (Plus or Minus Two)

George Miller Average person holds about 7 + 2 items in

STM Phone numbers, social security numbers,

etc. Chunking can help increase capacity

Grouping information into meaningful units

Number of chunks that can be held decreases as chunks get larger

The Duration of Short-term Memory: It’s Yours for 30 Seconds

Once passed into STM, information can only be kept for 30 seconds without some type of processing

Maintenance rehearsal Repetition of material in short-term

memory

How We Transfer Information from Short-Term to Long-Term Memory

Maintenance rehearsal produces a weak transfer into LTM

Elaborative rehearsal Forming associations, or mental

connections, between information in STM to information already stored in LTM

Levels of Processing Model

Fergus Craik and Robert Lockhart The more thoroughly or deeply you

process information, the stronger the transfer to LTM

Both maintenance and elaborative rehearsal allow for transfer to LTM, but elaborative rehearsal involves a deep level of processing Difference between simply repeating

material and thinking about material Pays off in terms of storage and retrieval

of information

The Capacity of Long-term Memory

LTM is where information is stored for long periods of time

Limitless capacity Capacity problems are likely related to

lack of focus or lack of space in STM or working memory

Major Functions of Memory

Encoding—how we break down the information coming into our senses

Storage—keeping memories in our long term memory

Retrieval—process in which information in your memory can be recalled

Encoding in Long-term Memory

Encoding occurs in several forms Acoustic (sound), visual, semantic

Semantic encoding is most common Stores general meaning, rather than all

sensory details Encode and connect new information

with already stored information in LTM

Organization in Long-term Memory

Schemata – generalized knowledge structures Filing systems for knowledge about

particular concepts Default values for missing information

Various types of schemata Object, abstract concept, person Stereotypes Scripts

Types of Long-Term Memory

Declarative memory – explicit memory for knowledge easily verbalized (e.g. names, dates)

Two parts of declarative memory Semantic memory – concepts Episodic memory – memory for events

▪ Also called autobiographical memory▪ Memories have personal awareness

Gender and Autobiographical Memory

Females betters able to recall emotional childhood memories

Females tend to organize autobiographical memories in more diverse categories (i.e. more elaborative processing)

Procedural Memory

Memory that is not readily put into words - procedures for skills such as riding a bike, tying shoe, etc.

Often is implicit memory (unconscious) Tends to last longer than declarative

memory Studies from people with amnesia suggest

that procedural memory is a separate memory system

Retrieval, Recognition, and Recall

Retrieval – act of moving information from LTM back to working memory or consciousness Probe or cue sent in search of stored

memory traces Recall task – probe relatively weak and

does not contain much cue information (e.g. essay question)

Recognition task – probe stronger, contains more cue information (e.g. multiple choice question)

Memory must be available and accessible

Tips for Improving Memory

Pay attention, minimizing distractions Do not cram for exams

Distributed is better than massed practice

Use elaborative rehearsal Use overlearning Use mnemonic devices

Acronyms (APA), acrostics(rhyme or saying)▪ Remember the major functions of memory:

Ellen stopped remembering (encoding, storage, retrieval)

Is Memory Accurate?

Flashbulb memories – detailed memories of emotionally charged events These memories are not always accurate Store gist of information in LTM, not

exact details Examples of flashbulb memories:

▪ Attacks on 9/11▪ Assassination of JFK ▪ Birth of child▪ Wedding

Eyewitness Memory

Elizabeth Loftus Eyewitness memory can be manipulated

by expectations Memories can be permanently altered by

things that happen after we encode memories (false memories) False memories become part of memory

of original event

Myers’ PSYCHOLOGY

(7th Ed)

Chapter 9Memory

James A. McCubbin, PhDClemson University

Worth Publishers

Memory

Memory persistence of learning over

time via the storage and retrieval of information

Flashbulb Memory a clear memory of an

emotionally significant moment or event

Memory

Memory as Information Processing similar to a computer

write to file save to disk read from disk

Encoding the processing of information into the

memory system i.e., extracting meaning

Memory

Storage the retention of encoded

information over time Retrieval

process of getting information out of memory

Memory

Sensory Memory the immediate, initial recording

of sensory information in the memory system

Working Memory focuses more on the processing

of briefly stored information

Memory

Short-Term Memory activated memory that holds a few

items briefly look up a phone number, then

quickly dial before the information is forgotten

Long-Term Memory the relatively permanent and

limitless storehouse of the memory system

A Simplified Memory Model

Externalevents

Sensorymemory

Short-termmemory

Long-termmemory

Sensory inputAttention to importantor novel information

Encoding

Encoding

Retrieving

Encoding: Getting Information In

Encoding

Effortful Automatic

Encoding

Automatic Processing unconscious encoding of incidental

information space time frequency

well-learned information word meanings

we can learn automatic processing reading backwards

Encoding

Effortful Processing requires attention and conscious

effort Rehearsal

conscious repetition of information to maintain it in consciousness to encode it for storage

Encoding

Ebbinghaus used nonsense syllables TUV ZOF GEK WAV the more times practiced on Day 1,

the fewer repetitions to relearn on Day 2

Spacing Effect distributed practice yields better

long- term retention than massed practice

Encoding

20

15

10

5

08 16 24 32 42 53 64

Time in minutestaken to relearnlist on day 2

Number of repetitions of list on day 1

Encoding: Serial Position Effect

12

Percentage of words

recalled

0

90

80

70

60

50

40

30

20

10

Position of word in list

1 2 3 4 5 6 7 8 9 10 11

Serial Position Effect--tendency to recall best the last items in a list

What Do We Encode?

Semantic Encoding encoding of meaning including meaning of words

Acoustic Encoding encoding of sound especially sound of words

Visual Encoding encoding of picture images

Encoding

Encoding

Imagery mental pictures a powerful aid to effortful processing,

especially when combined with semantic encoding

Mnemonics memory aids especially those techniques that use

vivid imagery and organizational devices

Encoding

Chunking organizing items into familiar,

manageable units like horizontal organization--

1776149218121941 often occurs automatically use of acronyms

HOMES--Huron, Ontario, Michigan, Erie, Superior

ARITHMETIC--A Rat In Tom’s House Might Eat Tom’s Ice Cream

Encoding: Chunking

Organized information is more easily recalled

Encoding Hierarchies

complex information broken down into broad concepts and further subdivided into categories and subcategories Encoding

(automatic or effortful)

Imagery(visualEncoding)

Meaning(semanticEncoding)

Organization

Chunks Hierarchies

Storage:Retaining Information

Iconic Memory a momentary sensory memory of

visual stimuli a photographic or picture image

memory lasting no more that a few tenths of a second

Echoic Memory momentary sensory memory of

auditory stimuli

Storage:Short-Term Memory

Short-Term Memory limited in

duration and capacity

“magical” number 7+/-2

0102030405060708090

3 6 9 12 15 18

Time in seconds between presentationof contestants and recall request

(no rehearsal allowed)

Percentagewho recalledconsonants

Storage:Long-Term Memory

How does storage work? Karl Lashley (1950)

rats learn maze lesion cortex test memory

Synaptic changes Long-term Potentiation

increase in synapse’s firing potential after brief, rapid stimulation

Strong emotions make for stronger memories some stress hormones boost learning and

retention


Amnesia--the loss of memory Explicit Memory

memory of facts and experiences that one can consciously know and declare

also called declarative memory hippocampus--neural center in limbic system

that helps process explicit memories for storage

Implicit Memory retention independent of conscious

recollection also called procedural memory

Storage: Long-Term Memory Subsystems

Types oflong-termmemories

Explicit(declarative)

With consciousrecall

Implicit(nondeclarative)

Without conscious recall

Facts-generalknowledge(“semanticmemory”)

Personally experienced

events(“episodic memory”)

Skills-motorand cognitive

Dispositions-classical and

operant conditioning

effects


MRI scan of hippocampus (in red)

Hippocampus

Retrieval: Getting Information Out

Recall measure of memory in which the

person must retrieve information learned earlier

as on a fill-in-the blank test Recognition

Measure of memory in which the person has only to identify items previously learned

as on a multiple-choice test

Retrieval

Relearning memory measure that

assesses the amount of time saved when learning material a second time

Priming activation, often

unconsciously, of particular associations in memory

Retrieval Cues

0

10

20

30

40

Water/land

Land/water

Water/water

Different contexts for hearing and recall

Same contexts for hearing and recall

Land/land

Percentage ofwords recalled

Retrieval Cues

Deja Vu (French)--already seen cues from the current situation may subconsciously

trigger retrieval of an earlier similar experience "I've experienced this before."

Mood-congruent Memory tendency to recall experiences that are consistent

with one’s current mood memory, emotions, or moods serve as retrieval

cues State-dependent Memory

what is learned in one state (while one is high, drunk, or depressed) can more easily be remembered when in same state

Retrieval Cues

After learning to move a mobile by kicking, infants had their learning reactivated most strongly when retested in the same rather than a different context (Butler & Rovee-Collier, 1989).

Forgetting

Forgetting as encoding failure Information never enters the long-

term memory

Externalevents

Sensorymemory

Short-term

memory

Long-term

memory

Attention

Encoding

Encoding

Encodingfailure leadsto forgetting

Forgetting

Forgetting as encoding failure

Which penny is the real thing?

Forgetting

Ebbinghaus forgetting curve over 30 days-- initially rapid, then levels off with time12345 10 15 20 25 30

10

20

30

40

50

60

0

Time in days since learning list

Percentage oflist retainedwhen relearning

Forgetting

The forgetting curve for Spanish learned in school

Retentiondrops,

then levels off

1 3 5 9½ 14½ 25 35½ 49½Time in years after completion of Spanish course

100%

90

80

70

60

50

40

30

20

10

0

Percentage oforiginal

vocabularyretained

Retrieval

Forgetting can result from failure to retrieve information from long-term memory

Externalevents

Attention

Encoding

Encoding

Retrieval failureleads to forgetting

Retrieval

Sensorymemory

Short-termmemory

Long-termmemory

Forgetting as Interference

Learning some items may disrupt retrieval of other information Proactive (forward acting)

Interference disruptive effect of prior learning on

recall of new information Retroactive (backwards acting)

Interference disruptive effect of new learning on

recall of old information

Forgetting as Interference

Forgetting

Retroactive Interference

Without interferingevents, recall isbetter

After sleep

After remaining awake

1 2 3 4 5 6 7 8Hours elapsed after learning syllables

90%

80

70

60

50

40

30

20

10

0

Percentageof syllables

recalled

Forgetting

Forgetting can occur at any memory stage

As we process information, we filter, alter, or lose much of it

Forgetting- Interference

Motivated Forgetting people unknowingly revise

memories Repression

defense mechanism that banishes from consciousness anxiety-arousing thoughts, feelings, and memories

Memory Construction

We filter information and fill in missing pieces

Misinformation Effect incorporating misleading

information into one's memory of an event

Source Amnesia attributing to the wrong source an

event that we experienced, heard about, read about, or imagined (misattribution)

Memory Construction

Eyewitnesses reconstruct memories when questioned

Depiction of actual accident

Leading question:“About how fast were the carsgoing when they smashed intoeach other?”

Memoryconstruction

Memory Construction

Memories of Abuse Repressed or Constructed?

Child sexual abuse does occur Some adults do actually forget such episodes

False Memory Syndrome condition in which a person’s identity and

relationships center around a false but strongly believed memory of traumatic experience

sometimes induced by well-meaning therapists

Memory Construction

Most people can agree on the following: Injustice happens Incest happens Forgetting happens Recovered memories are commonplace Memories recovered under hypnosis or

drugs are especially unreliable Memories of things happening before

age 3 are unreliable Memories, whether false or real, are

upsetting

Improve Your Memory

Study repeatedly to boost recall Spend more time rehearsing or

actively thinking about the material

Make material personally meaningful

Use mnemonic devices associate with peg words--something

already stored make up story chunk--acronyms

Improve Your Memory

Activate retrieval cues--mentally recreate situation and mood

Recall events while they are fresh-- before you encounter misinformation

Minimize interference Test your own knowledge

rehearse determine what you do not yet

know

3-1: Structure of the Human Brain (Figure 3-6)

Teresa M. McDevitt, Jeanne Ellis OrmrodChild Development and Education

Copyright ©2002 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

3-2: Neurons in the Brain (Figure 3-5)




3-3: Examples of Risk Factors for Healthy Neurological Development (Table 3-1)




5 BASIC PRINCIPLES OF DARWINIAN EVOLUTION THEORY[FROM: MICHAEL SHERMER’S (2002) In Darwin’s Shadow: The life and Science of Alfred Russel Wallace. New York, NY: Oxford University Press, p. 207.]

EVOLUTION: CHANGE (in behavior)THROUGH TIME. DESCENT WITH MODIFICATION: THE MODE OF EVOLUTION BY

BRANCHING COMMON DESCENT. GRADUALISM: CHANGE (in behavior) IS SLOW, STEADY, STATELY.

NATURA NON FACIT SALTUS. GIVEN ENOUGH TIME EVOLUTION CAN ACCOUNT FOR THE ORIGIN OF NEW SPECIES.

MULTIPLICATION OF SPECIATION: EVOLUTION PRODUCES NOT JUST NEW SPECIES (behavior), BUT AN INCREASING NUMBER OF NEW SPECIES (behaviors).

NATURAL SELECTION: THE MECHANISM OF EVOLUTIONARY CHANGE CAN BE SUBDIVIDED INTO FIVE STEPS: (SEE NEXT SLIDE).

FIVE STEPS OF NATURAL SELECTION

1. POPULATIONS [behaviors] TEND TO INCREASE INDEFINITELY IN A GEOMETRIC RATIO. [FROM OBSERVATION]

2. IN A NATURAL ENVIRONMENT, HOWEVER, POPULATION [behavior] NUMBERS STABILIZE AT A CERTAIN LEVEL. [FROM OBSERVATION]

THERE MUST BE A “STRUGGLE FOR EXISTENCE” SINCE NOT ALL ORGANISMS [behaviors] PRODUCED CAN SURVIVE. [FROM INFERENCE]

THERE IS VARIATION IN EVERY SPECIES [behaviors]. [FROM OBSERVATION]

IN THE STRUGGLE FOR EXISTENCE, THOSE VARIATIONS THAT ARE BETTER ADAPTED TO THE ENVIRONMENT LEAVE BEHIND MORE OFFSPRING THAN THE LESS WELL ADAPTED INDIVIDUALS, ALSO KNOWN AS DIFFERENTIAL REPRODUCTIVE SUCCESS. [FROM INFERENCE]

BEHAVIORISTS’:BASIC ASSUMPTIONS OF BEHAVIORISM

PRINCIPLES OF LEARNING SHOULD APPLY EQUALLY TO DIFFERENT BEHAVIORS AND TO DIFFERENT SPECIES OF ANIMALS

LEARNING PROCESSES CAN BE STUDIED MOST OBJECTIVELY WHEN THE FOCUS OF STUDY IS ON STIMULI AND RESPONSES.

INTERNAL PROCESSES ARE LARGELY EXCLUDED FROM SCIENTIFIC STUDY

LEARNING INVOLVES A BEHAVIOR CHANGE ORGANISMS ARE BORN AS BLANK SLATES (tabula rasa). LEARNING IS LARGELY THE RESULT OF ENVIRONMENTAL

EVENTS. THE MOST USEFUL THEORIES TEND TO BE PARSIMONIOUS

ONES.

Concept Map:Behavioral Approaches

Approaches to Learning

Social Cognitive Approachesto Learning

SOCIAL COGNITIVEAPPROACHES TO

LEARNING

Bandura’s SocialCognitive TheoryBandura’s SocialCognitive Theory

Evaluating theSocial Cognitive

Approaches

Evaluating theSocial Cognitive

Approaches

Cognitive Behavior

Approaches

ObservationalLearning


Bandura’s social cognitive theory Social cognitive theory Reciprocal determinism model Self-efficacy

Bandura’s Reciprocal Determinism Model of Learning

BBehavior

P/CPerson and

cognitive factors

EEnvironment


Observational learning What is observational learning? The classic Bobo doll study Bandura’s contemporary model of

observational learning▪ Attention▪ Retention▪ Motor reproduction▪ Reinforcement of incentive conditions


Cognitive behavior approaches and self-regulation Cognitive behavior approaches

▪ Self-instructional methods


Self-regulatory learning▪ A model of self-regulatory learning

Self-Evaluationand Monitoring

Putting a Plan intoAction and Monitoring It

Goal Setting andStrategic Planning

Monitoring Outcomesand Refining Strategies

Self Regulated Learning:From Social/Cognitive Theory.

Key people:Bandura; Schunk; Zimmerman.

Key elements:

Goal Setting Planning Self-motivation (intrinsic motivation) Attention control Application of learning strategies Self-monitoring Self-evaluation Self-reflection

General Assumptions of Cognitive Theories

Some Learning Processes may be unique to human beings.

Cognitive processes are the focus of study. Objective, systematic observations of people’s

behavior should be the focus of scientific inquiry; however, inferences about unobservable mental processes can often be drawn from behavior.

· Individuals are actively involved in the learning process.

· Learning involves the formation of mental representations or associations that are not necessarily reflected in overt behavior changes.

Implications of Cognitive Theories

Cognitive processes influence learning. As children grow, they become capable of

increasingly more sophisticated thought. People organize the things they learn.· New information is most easily acquired when

people can associate it with things they have already learned.

· People control their own learning.

Some key Cognitive theorists

Jean Piaget (French) Lev Vygotsky (RUSSIAN) Edward Tolman (American) Jerome Bruner (American) Kurt Lewin (German)

Kurt Lewin (From Alfred Marrow’s book)

BH = f (P+E)

BARRIER

GOAL

REGION

PSYCHOLOGICAL LIFE SPACE

PERSON

NEEDS

ABILITIES

-

+

FOREIGN HULL VECTORS

VALENCES

Concept Map: Chapter Eight Overview

The Cognitive Information-Processing Approach

Characteristics of theInformation-Processing

Approach

Characteristics of theInformation-Processing

Approach

THE COGNITIVE INFORMATION-

PROCESSING APPROACH

Exploring theInformation-Processing

Approach


Exploring the information-processing approach Cognitive psychology


Characteristics of the information-processing approach Thinking Change mechanisms

▪ Encoding▪ Automaticity▪ Strategy construction▪ Transfer

Self-modification▪ Metacognition

Memory

MEMORY

What isMemory?What is

Memory?Retrieval and

ForgettingRetrieval and

Forgetting

StorageEncoding

Memory

What is memory?

ENCODING

Gettinginformationinto memory

STORAGE

Retaininginformationover time

RETRIEVAL

Takinginformationout of storage

Memory

Encoding Rehearsal Deep processing

▪ Levels of processing theory Elaboration Constructing images Organization

▪ Chunking

Memory

Storage Memory’s time frames

▪ Sensory memory▪ Short-term (working) memory

▪ Memory span

▪ Long-term memory

Key Ideas in Information Processing Theory




I Sensation and Perception

II AttentionA. Distractibility decreases; sustained attention increases

B. Attention becomes increasingly purposeful

III Working Memory A. Processing speed increases

B. Children acquire more effective cognitive processes

C. The physical capacity of working memory may increase somewhat

IV Long-Term MemoryA. The amount of knowledge stored in long-term

memory increases

B. Knowledge becomes increasingly symbolic in nature

C. Children’s knowledge about the world becomes increasingly integrated

D. Children’s growing knowledge base facilitates more effective learning

5-1: A model of the human information processing system (Figure 5-1)




Atkinson and Shiffrin’s Theory of Memory

Baddeley’s Model of Memory

Visuospatialscratchpad

Centralexecutive

Articulatoryloop

Storage: Long-Term Memory’s Contents

Long-term memoryLong-term memory

Nondeclarative(implicit)

Nondeclarative(implicit)Declarative

(explicit)Declarative

(explicit)

Episodic memoryEpisodic memory Semantic memorySemantic memory

Memory

Storage Content knowledge and how it is

represented in long-term memory▪ Content knowledge▪ Network theories▪ Schema theories

▪ Schema▪ Script

Memory

Retrieval and forgetting Retrieval

▪ Serial position effect▪ Primacy effect▪ Recency effect▪ Encoding specificity principle▪ Recall▪ Recognition

Memory

Retrieval and forgetting Forgetting

▪ Cue-dependent forgetting▪ Interference theory▪ Decay theory

Abraham Maslow’s

Perspectives on motivation The humanist perspective

▪ Maslow’s hierarchy of needs▪ Physiological▪ Safety▪ Love and belongingness▪ Esteem▪ Self-actualization

memory - form and function

Health & Medicine