UNIT 3 – AREA OF STUDY 2: MEMORY Chapter 6: Memory
Feb 25, 2016
UNIT 3 – AREA OF STUDY 2:
MEMORYChapter 6: Memory
STUDY D
ESIGN
, 2010 - 2014This knowledge includes:
Comparison of models for explaining human memory: Atkinson-Shiffrin’s multi-store model of memory including
maintenance and elaborative rehearsal, serial position effect and chunking
Alan Baddeley and Graham Hitch’s model of working memory: central executive, phonological loop, visuo-spatial sketchpad, episodic buffer
levels of processing as informed by Fergus Craik and Robert Lockhart
organisation of long-term memory including declarative and episodic memory, and semantic network theory
Neural basis of memory: role of the neuron in memory formation informed by the
work of E. Richard Kandel roles of the hippocampus and temporal lobe consolidation theory memory decline over the lifespan amnesia resulting from brain trauma and neurodegenerative
diseases including dementia and Alzheimer’s disease
UNIT 3 – AREA OF STUDY 2: MEMORYASSESSMENT TASKS
S/N Work Requirements Glossary – due 15th May, 2012 Workbook which includes the learning activities from textbook
as per the slides and completed activities/tasks given by your teacher (Min. 80% complete) – due 15th May, 2012 or earlier
90% attendance rate
SACs ERA
Week 3 (approx.) /30 marks
Test Week 8 (approx.) /20 marks
NoteIf you are away during a SAC – you MUST hand in an original
medical certificate in order to re sit the SAC.
This is a VCCA requirement, and parents or students who only
phone or email do not satisfy this requirement, and if a medical certificate is not produced, a
score of 0 will be given
CHAPTER 6 – WHAT’S COMING UP? Defining memory Models for explaining human memory- The Atkinson-Shiffrin multi store model- Sensory memory- Short term memory- Craik & Lockharts levels of processing framework- Braddeley & Hitch’s model of working memory- Long Term memory- Serial position effect Neural basis of memory- Role of the neuron in memory formation - Role of hippocampus & temporal lobe - consolidation theory- Amnesia resulting from brain trauma & neurodegenerative
diseases- Memory decline over the lifespan
WHO REMEMBERS ??
MODELS OF MEMORY
How is information processed?
Memory systems
Memory is not a ‘single organ’ or a single ‘thing’, rather it consists of a collection of complex interconnected and interacting systems
We do not have a memory, but we have different memory systems which share a common function of:
our perceptual systems, eg vision are constantly inputting information, however the brain must work out what to attend to, process and store in memory, and what not to!
storing information(learned through
experience)
retrieving the information (when needed)
Processing different information
Storing information (in different ways & types of
information)
DEFINING MEMORY Memory is often defined as the storage and retrieval of
information acquired through learning. the existence of memory indicates that learning
has occurred and the memory is the internal record or representation of an event &/or experience.
Memory is also defined as requiring and as information processing (think… like a computer)
Memory as information processing - Encoding – converting information to a useable form Storage – retaining information in memory Retrieval – information recovered from memory when
needed All three processes are required and if any one is not
included, the memory will not form. (see fig 6.4 on page 291)
Memory as an info-processing system
Memory is an active (uses energy) information-processing system that: Receives, Organises Stores &recovers information
Memory actively alters and organises information, then stores it so that it can be easily retrieved when needed
There are 3 key processes involved in these systems. If any of these processes fail, memory will fail
An additional aspect of the Atkinson & Shiffrin human multi store model included:
Structural features & Control processes.
Incoming sensory input
• Info is converted for storage
Encoding • Info is retained in brain
Storage• Info is
recovered when needed
Retrieval
MEMORY LIKE A COMPUTER ????
Encoding
Storage
Retrieval
= hitting the letters on the key board -> it goes into the computer
= we hit ‘save’ -> we name the file and store the information for later on when we save the file
= process of getting past information back -> we need to use the right ‘cues’ in order to get the information back, but if we do then we have the original information back!
READ BOX 6.3 – ON P 291-292
Automatic & effortful encoding
Encoding can be spilt further into categories.read, define & provide and example of automatic
encoding & effortful encoding
LEARNING ACTIVITY 6.2
Page 292 of your text, Questions 1,2 & 3
MODEL’S FOR EXPLAINING HUMAN MEMORY
As the human memory is complex and multifaceted, is it NOT studied together, rather it is broken down into pieces or sections, each being studied separately.
Each of these is referred to as a MODEL
The three main theories that explain how human memory functions are:1. Atkinson-Shiffrin multi-store model2. Baddeley and Hitch’s model of working
memory3. Craik and Lockhart’s levels of
processing framework
ATKINSON-SHIFFRIN’S MULTI-STORE MODEL OF MEMORY
Based in the 1960’s Proposed a shift in the single memory model =>
assumption that human memory has several systems/processes involved.
By Richard Atkinson & Richard Shiffrin – Americans. This model was also called/considered modal model, as
it merged and represented many other models during this time.
It is also known as the stage model, as it put forward that the flow of information moves in stages through each component of memory.
Information passes through 3 levels of memory as it is encoded, stored and retrieved, and these 3 levels are sensory register, short term store & long term store
Sensory register• The entry point for all new
information into memory from the external environment
• Stores vast amount of incoming visual information, for 100’s milliseconds
If information is attended to, it moves
into short term memory store Short term store
• A temporary working memory• Here we can manipulate information from every
day/common tasks• Holds all information that we are aware of at
that point in time• Has a limited capacity – 7 items at 1 time• Only held for about 30 sec unless we make an
effort to keep it there (attend to it), eg rehearsal
Rehearsal at time point critical for more permanent storage (LTM)
Long term store• Information held relatively permanently in an highly organised way• Essentially can be an unlimited capacity• Unlike sensory register & short term store – information in long term store does not
usually decay and can stored for …… a whole lifetime• According to Atkinson & Shiffrin – it is our inability to retrieve required information
that results ineffective search strategies• Problems with retrieval may also be due to ‘interference’ with the information and
this results in a disruption in the retrieval process
If informatio
n is not attended to, it is
lost
Atkinson-Shiffrin multi-store model
Sensory Memory
Long-term
Memory
Short-term
MemorySensory
info
Info not paid attention to…
Various reasons
Not rehearsed or
encoded
Lost from sensory memory
Displaced from short-term memory
Paid attention to info
Info encoded or rehearsed
Rehearsal
Retrieval
Forgotten
CRIMD
STRUCTURAL & CONTROLLED PROCESSES
Structural features of memory are the permanent features that do not alter from situation to situation – they are three levels of information processing: Sensory memory, Short term memory (STM) & Long term memory (LTM)
Control processes are the activities the individual does to process the information (eg they have ‘control’ over what they attended to and process) Attention – no information will be encoded if we don’t
pay attention to it Rehearsal – process that goes over information and
helps it be storedBut all of this was developed over 40 years ago ….. And we know have more knowledge …
EVALUATING ATKINSON & SHIFFRIN
Advantages Limitations
Identified characteristics of short term store as being different and apart from long term memory
Recognised the importance of short term store & its fundamental roles
Manitence and rehearsal are still relevant, although now more complex
Despite some newly learnt differences, still held as the original multi store model, although now just more complex
It is now clear that information does not ‘just flow’ as described in Atkinson & Shiffrin’ 3 stage sequence
There is a separate sensory register for auditory information & haptic (touch) information – and maybe even more now referred to as a sensory memory system
Short term store now believed to be a much more complex system
Different types of rehearsal have been identified in short term memory
Long term store is no longer a single store -> rather it includes more complex systems & structures of storage.
LEARNING ACTIVITY 6.3
Page 295 of your text, Questions 1-7
Stages of memory – Sensory Memory Sensory Memory
Entry point of memory Capacity to store all sensory stimuli
(unlimited) Stored as the original form of stimulus
(buffer – need more processing before it can be stored)
Not consciously aware of most of the info in sensory stage, directing attention to it is what causes transfer to short-term memory
Incoming stimuli is stored as a memory trace in different sensory registers based on the type of sense Iconic memory – visual Echoic memory - auditory
Sensory Memory includes Iconic memory ( I as in eye)
Visual images are stored here for about 0.2-0.4 seconds
Stored as overlapping imagesAllows perception of flowing movement during a
film, or a figure drawn with a sparkler at night
Echoic memory (e as in ear)Sound stimuli are stored here for around 3-4
secondsThis is longer than in iconic memory as sound
takes longer to produceAllows comprehension of speech by connecting
individual sounds coherently into words and sentences
LEARNING ACTIVITY 6.5
Page 299 of your text, Questions 1-7
NOTE: THERE IS ALSO AN INTERESTING READ IN BOX
6.4 ON PHOTOGRAPHIC MEMORY
Stages of memory – Short-term memory Activity: Capacity of STM
Read aloud the following series of numbers and ask students to recall each line in order. 6, 4, 7 (3 items) 9, 0, 1, 8 (4 items) 4, 3, 5, 7, 2 (5 items) 7, 1, 3, 8, 9, 4 (6 items) 3, 6, 8, 4, 9, 1, 5 (7 items) 2, 6, 4, 9, 1, 5, 7, 3 (8 items) 1, 7, 5, 8, 6, 3, 9, 2, 4 (9 items) 2, 6, 7, 3, 5, 4, 9, 1, 8, 3 (10 items)
On average, how many numbers did each person recall from each list? This is the capacity of STM.
Activity: Duration of STM Students learn the following sequence of numbers 4, 5, 3, 6, 2, 7, 8 Test immediately, then after 2 minutes How many people remembered the sequence? This is duration
of STM
Stages of memory: Short-term memory
Short-term memory (STM) is a memory system that has a limited capacity and duration
It also stores the information in an encoded format
Described as the “seat of conscious thought” – information only registers in STM once it is paid attention to – in conscious awareness
Duration of STMWithout rehearsal (active use), recall starts to
decline after about 12 seconds and is almost completely gone after 18 seconds (occasionally can last up to 30 sec)
Using rehearsal, information can be retained indefinitely in STM
LEARNING ACTIVITY 6. 7
Page 307 of your text, Questions 1-7, don’t worry about Q 8.
Capacity of STMThe amount of pieces of information that can be
stored in STM is 7 ± 2 (between 5-9 items)Adding in more items displaces (pushes out) existing
items in STM – this is called displacement, shown below
Recalling information from long-term memory can also displace items from STM
Information is lost primarily within STM by either displacement (pushing out) or by decay (not being used- think fruit!)
Short-term memory
Now becomes ..
SHORT TERM MEMORY
Capacity of STM cont…..
Chunking is a method of increasing the capacity of STMDefiniton: grouping or separate bits of information
into a larger single chunk of information.Separate pieces of info are remembered as single
units (groups info into chunks)Only similar info can be chunked together (chunking)Still only retain 7 ± 2 chunksChunks can be numbers, images, words, sentences,
phrases and even abbreviationsThis is why we have phone numbers broken into parts
…… 5427 2600 rather than 54272600.
SHORT TERM MEMORYSTM as working memory Term working memory is used to emphasise the active
part of memory where information we are aware of constantly, is actively ‘worked on; in a variety of ways
Enables us to use the information in sensory memory and move it to LTM
Often we combine information from sensory memory and LTM to perform mental processes, such as emotions, comprehension, problem solving, planning & daydreaming.
So this ‘working memory’ provides a temporary storage facility and mental workspace for information currently being used within a conscious cognitive activity.
The STM working memory is often compared to a computer
Effects of rehearsal Rehearsal is the process of actively and consciously
manipulating information to keep it in STM for longer than the normal 18 sec. (Increases duration)
Maintenance rehearsal Repeating info over and over usually vocally (out loud)
or sub-vocally (in your head) Works indefinitely to keep info in STM Does not always transfer info into long-term memory
Elaborate rehearsal Links new info to existing knowledge in a meaningful
way More active than maintenance rehearsal (requires more
effort) Very effective in transferring info into long-term
memory, especially when using personal link (self-reference effect)
EFFECTS OF REHEARSAL
Sensory Memory
Long-term
Memory
Short-term
Memory
Info not paid attention to…
Various reasons
Not rehearsed or
encoded
Lost from sensory memory
Displaced from short-term memory
Paid attention to info
Elaborative Rehearsal
Maintenance
Rehearsal
Retrieval
Forgotten
CRIMD
Sensory info
LEARNING ACTIVITY 6. 10
Page 312 – we can do this one as a class!
Stages of memory – Long-term memory Long-term memory (LTM) is the relatively
permanent memory system that has potentially unlimited capacity and duration (life-long) Info in LTM is inactive (not in use) and we are not
consciously aware of it until it is retrievedDue to the sheer volume of info in LTM, we use cues
(intentional or unintentional) to speed up the process of retrieval
Cues enable retrieval of specific info, not the entire contents of LTM – usually very efficient and very fast
Once retrieved, the info is stored in STM until it is no longer needed/in use. It is then transferred back into LTM
Failure to retrieve info from LTM is usually due to poor organisation during encoding and storage, or an inappropriate cue was used during retrieval
Info is encoded in terms of its meaning (semantically)
Types of long-term memory Memories in LTM are relatively permanent or at least
very longlasting Forgetting is most likely due to a failure to retrieve
info – poor encoding or poor cue Retrieval cues: a stimulus that assists in the process
of locating and retrieving information stored in memory.
There are two major types of LTM (LTM stores):① Procedural memory (Implicit memories – “how?”)
Knowing how to do stuff – actions and activitiesOften difficult to explain this knowledgeUsually learnt through observation and practiceNot usually consciously recalledE.g. making a cup of tea/riding a bike
Types of long-term memory② Declarative memory (Explicit memories –
“What?”)Memories of facts and/or eventsUsually consciously recalledTwo types of declarative memory:a) Episodic memory
Memories of specific events or personal experiences Include references to “when” and “where”
b) Semantic memory Memories of general academic knowledge Facts not necessarily related to a specific place or
time Include references about “what” and “who”
Characteristics of the stages of memoryStage
of memo
ryFunction Form of
storageCapac
ity Duration
Sensory memory (SM)
•Receives sensory information (stimuli) from environment
Original sensory formE.g. lingering sense of sound or pressure
Unlimited
•Varies based on sensation•Usually between 0.2 – 4 sec•Occasionally up to 10 sec
Short-term memory (STM)
•Receives info from SM•Receives info from LTM
Encoded in terms of physical properties of stimuliE.g. Starts with L
7 ±2 pieces or chunks of info
•Usually 18-20 sec•Occasionally up to 30 sec
Long-term memory (LTM)
•Storehouse for encoded info coming from STM
Encoded in terms of semantics - meaning
Unlimited
•Potentially permanent
Levels of processing framework – CRAIK AND LOCKHART
Craik and Lockhart proposed a framework of memory that emphasised the importance of the level of processing in how well information is stored in LTM
Info is stored best in LTM semantically (by meaning) so if the meanings of concepts are processes during learning, they are more likely to be recalled later – elaborate rehearsal is more effective for LTM than maintenance rehearsal
The deeper the level of processing (more elaborate encoding) the better the recallVisual encoding – “is there a letter k in the word?”Acoustic encoding – “does it rhyme with hat?”Semantic encoding – “is it a synonym of difficult?”
Levels of processing framework
Shallow processing
Visual encoding
What the word looks like
Colours, shapes and patterns detected
Intermediate processing
Acoustic encoding
What the word sounds like
Item is identified
Deep processing
Semantic encoding
What the word means
Meaningful associations are made
Levels of processing or depth are hard to define specifically and to measure
Despite this problem the idea of better processing and therefore better storage is supported widely by research
Craik and Lockhart
Model of working memory – BADDELEY AND HITCH’S
Baddeley and Hitch’s model of working memory describes STM as a functional system with three components that work independently but can also interact:
① Phonological loop (Verbal working memory) Verbal information is stored in a sound-based form
(phonological) Only hold about 2 sec worth of info (around 7 items
depending on length of words)② Visuo-spatial sketchpad (Visual working
memory) Visual info is anything you can see or imagine, spatial
info is position and location of objects in space Also has limited duration and capacity (around 4
items)
Model of working memory – BADDELEY AND HITCH’S
③ Central executive Controls attention Integrates information from the phonological loop and visuo-
spatial sketchpad with info from LTM Coordinates the flow of info between the working memory
system and LTM Manipulates the info held in the phonological loops and visuo-
spatial sketchpad – the working component of the model of working memory
Episodic buffer (a fourth component added in 2000) A sub-system of the working memory that enables the
different components to interact with LTM Has limited capacity (about 4 chunks of info) Can hold info in any form and so can integrate phonological
loop and visuo-spatial sketchpad – temporary workspace where various pieces of info can be put together in a meaningful way
Controlled by central executive
Model of working memory
Sensory input
Phonological loop
Visuo-spatial sketchpad
Central Executive
Episodic Buffer
Long-Term Memory
Rehearsal
Rehearsal
ALAN BADDELEY AND GRAHAM HITCH’S MODEL OF WORKING MEMORY
Visio spatial SketchpadStorage of visual
and spatial information
Phonological Loop
storage of verbal speech informationEpisodic Buffer
Integrates useful LTM into what currently being worked on
Pulls together streams of different info into ‘episodes’
as a meaningful whole
The workbench
Central Executive
• Controls attention
• Integrates info from the two storage sub systems
• does the ‘working out’
•The seat of consciousness
BADDELEY & HITCH’S MODEL OF WORKING MEMORY
Read example on pg. 319
Once we have read it .....Going to party the following is:
- phonological loop stores the directions- Visio spatial sketchpad visualises the route- Central executive directs the Episodic buffer
to combine information from storage branches
- Episodic buffer also adds information from LTM
- Episodic buffer used as the mental ‘workbench’ to make adjustments
LEARNING ACTIVITY 6. 11&
LEARNING ACTIVITY 6. 18
Page 314 questions 1-6 &
page 320 questions 1, 4, 5, 7 ONLY
Again … just in cases you need to refresh
Stages of memory – LONG-TERM memory Long-term memory (LTM) is the relatively
permanent memory system that has potentially unlimited capacity and duration (life-long) Info in LTM is inactive (not in use) and we are not
consciously aware of it until it is retrieved Due to the sheer volume of info in LTM, we use cues
(intentional or unintentional) to speed up the process of retrieval
Cues ( retrieval cues) enable retrieval of specific info, not the entire contents of LTM – usually very efficient and very fast
Once retrieved, the info is stored in STM until it is no longer needed/in use. It is then transferred back into LTM
Failure to retrieve info from LTM is usually due to poor Organisation during encoding and storage, or an inappropriate cue was used during retrieval
Info is encoded in terms of its meaning (semantically)
Types of long-term memory Memories in LTM are relatively permanent or
at least very longlasting Forgetting is most likely due to a failure to
retrieve info – poor encoding or poor cue There are two major types of LTM (LTM
stores):① Procedural memory (Implicit memories –
“how?”)Knowing how to do stuff – actions and activitiesOften difficult to explain this knowledgeUsually learnt through observation and practiceNot usually consciously recalledE.g. making a cup of tea/riding a bike
Types of long-term memory
② Declarative memory (Explicit memories – “What?”)
Memories of facts and/or eventsUsually consciously recalledTwo types of declarative memory:a) Episodic memory
Memories of specific events or personal experiences Include references to “when” and “where”
b) Semantic memory Memories of general academic knowledge Facts not necessarily related to a specific place or
time Include references about “what” and “who”
TULVING (1983)
Tulving argues that semantic & episodic memory systems often work together in forming new memories – it isn't always one or the other.
In such instances, the memory that ultimately forms may consist of an autobiographical episode and semantic information.
Types of long-term memory Complete the table in your
workbooksTypes of Long Term MemoriesProcedural Memories
Definition: Example:
Declarative MemoriesDefinition: Example:
Episodic Memory Semantic MemoryExample: Example:
LEARNING ACTIVITY 6. 16
Page 325 questions 1-5 &
Organisation of Information in LTM
Long term memory’s most distinctive feature is its organisation of information
The task of retrieving information from LTM differs from the process of retrieving information from STM.
In short term memory, the search and retrieve tasks involve scanning only 7 + 2 items to locate the relevant information.
This 7 + 2 system doesn’t work with LTM, as there is such vast information to store, so there is a need for organisation to assist the storage and retrieval process.
BOUSFIELD & BOWER & CLARK Research into LTM has been studied for over 65 years now.
Research suggests:Bousfeild & Sedgewick, 1944 Information may be recalled in burst of information, pause
briefly ….. Then recall more information and so forth. This suggested the way people recalled items reflected the
way the items were organised in LTMBousfeild, 1953 Noticed that when asked to recall information, people would
recall the words in groups or clusters, without being awareHockenbury & Hockenbury, 2006 It is still believed today that there is some kind of logical
association in LTMBower & Clark, 1969 Found that words that were memorised in stories would
recall up to 90% of 12 words compared to only 15% of words remembered in any order
They concluded that the results from recall in LTM were improved using some organisation method.
LEARNING ACTIVITY 6. 19
Page 327 questions 1 – 10
These are great exam practice questions !
Semantic network theory Information is stored in LTM as series of
overlapping networks Each network is interconnected by meaningful links Each item of information or concept in the network
is called a node When a node in a network is activated (retrieved)
all other related nodes are made available (easier to retrieve) – spreading activation
Linking multiple concepts removes the need for multiple copies of the same information
The shorter or thicker the link between nodes, the stronger the association between them and the faster the retrieval
Think of the semantic network theory as towns as nodes and the highways & streets as links
SEMANTIC NETWORK THEORY IN PRACTICE
Semantic network theory – spreading activation (loftus &
collins)
Red
Fire Engine
Apple
Traffic lights
Blue
GreenYello
w
Fire
EmergencyPolic
e
Fireman
TrustworthyBrav
eCourag
e
LEARNING ACTIVITY 6. 21
Page 330 questions 1 – 2 ONLYThese are great exam practice
questions !
Serial position effect The serial position effect describes the differences in ability
to recall items in a list depending on their position in that list For immediate recall, typically items at the end of the list
are best recalled, then items at the start of the list, with items in the middle of the list least likely to be recalled
Recency effect Superior recall of items at the end of the list (most
recently experienced)Still in STM so easy to retrieve
Primacy effectSuperior recall of items at the start of the listHad the most time to rehearse for probably retrieved from
LTM Items from the middle of the list are no longer in STM and
haven’t had a chance to make LTM, so least likely to be recalled
Most clearly shown when tested immediately after exposure to the list. After 30 seconds recency effect is less apparent
Glanzer & Cuntiz (1966) research concluded that the STM & LTM must work together within the serial position effect. This was due recall better at both the start and end of the list, but with a delay of 30 seconds, this is beyond the limits of STM, and items at the start of the list were more likely stored in LTM.
http://withfriendship.com/images/h/38230/the-serial-position-effect.gif
Serial Position Effect
LEARNING ACTIVITY 6. 23
Page 333 questions 1 – 3
Neuron bases of memory Memories are stored throughout the brain linked together
by memory traces or “circuits” – interconnected neurons
However, different parts of the brain are involved in memory formation and retrieval to different degrees, and in different types of memories
New memories (either short or long term) are NOT stored in individual synapses but in the pattern of thousands of new interrelated connections
Looking for memories in a single nerve cell or synapse is a dead end
We know that there is a molecular basis to memory formation, what we do not know is exactly how thousands of these new connections hold our memories.
KANDELS SEA SLUGS Read pages 335 – 336
Kandel identified that there are physical changes to neurons during the formation of new memoriesWorked primarily with large sea slugs
(Aplysia californica)Has very simple Nervous System 20, 000 neuronsLargest observable neurons – can be seen
with the naked eye!
Stimulated the siphon (gill in the tail of slug that squirts water to move slug away from danger)
According to Kendal: STM – would withdraw gill more and more quickly Forgetting – an hour later the withdrawal was again slow,
progressively faster with continued stimulation Habituation – eventually the slug stopped responding to the
stimulation as it caused no damage, it had ‘learned’ that the shock was harmless
Retraction of the gills changes over time indicating memory, so Each day the slug would habituate more quickly than the day before
This suggest some kind of LTM lasting days or even weeks
By studying the neurons involved in this process he identified the changes that allowed the learning to take place
The neurons were physically changing!
These changes are called collectively Long Term Potentiation
LONG TERM POTENTIATION Neural basis for memory formation Synapse strength can increase in 3 ways- Release extra neurotransmitter- Increase number of receptor sites- Growth of new synapses
LONG TERM POTENIATION – EXPLICIT STM
New Receptor Formation
Stronger neural impulse in post synaptic neuron
So, we know all from sea slugs …….. Changes to neurons during memory formation are
collectively called Long-term potentiation and include: Increased volume of neurotransmitter (function) Increased connectivity to other neurons (structure)
Increased number of branches (dendritic spines) at the dendrite and/or axon terminal ends – reinforce existing connections
New synaptic junctions are formed between neurons – creating new memory traces /neural pathways
Short-term memory storage only tends to increase neurotransmitter production, while long-term storage produces functional and structural changes
As a memory is recalled, all the neurons in the memory trace are activated in sequence. The strength and number of connections between each neuron increases the ease and speed of recall
LEARNING ACTIVITY 6. 26
Page 337 questions 1 – 11
Hippocampus & Temporal lobe The hippocampus is a curved structure
found in each of the lower temporal lobes – one in each hemisphere (think horseshoes!)
Its about 3.5cm long and in humans have one in each of the lower region of the temporal lobe
Amygdala
Corpus callosumThalamus
THE MEDIAL TEMPORAL LOBE
THE HIPPOCAMPUS & MEDIAL TEMPORAL LOBE – DAMAGE AND
MEMORYHenry Molaison (H.M.) was a split brain patient who
also had his medial temporal lobe (inner surface area towards the temporal lobe that includes hippocampus & amygdala) removed to stop his extremely severe epilepsy
Medical success in preventing seizures, however it affected his memory
His personality and basic functioning remained unchanged, however he suffered major memory impairment, and left with permanent anterograde amnesia (Can’t form new LTM’s) Eg. While he could remember events from before his
surgery, he couldn’t remember anything that occurred after his surgery – couldn’t form new long-term memories
Other mental abilities and STM fine Eg. He could retain info in STM as long as he
maintained attention and actively rehearsed it, but could not transfer it into LTM
H.M’S HIPPOCAMPUS & MEDIAL TEMPORAL LOBE – DAMAGE & MEMORY
This established that the hippocampus and medial temporal lobe are involved or has a role in LTM formation,
It is NOT the storage site of long-term memories however
Evidence that LTM is most definitely a distinct sub system of memory (STM fine)
This demonstrated that the hippocampus & medial temporal lobe has an important role in the formation or encoding of new declarative explicit memories (semantic & episodic), but not in the formation & retrieval of implicit memories (procedural)
Consolidation Theory Information that is transferred from STM to LTM needs a
period of time to be properly and permanently encoded and stored – (‘consolidated’ or set - think concrete!)
The consolidation theory suggests that there are structural/physical changes to the neurons (long-term potentiation & axon growth) as new memories are formed.
These changes take time (consolidation phase) and the memory can be interfered with (changed) or erased (lost permanently) during this time.
The new memory is vulnerable for at least 30 minutes after being experienced.
The hippocampus and medial temporal lobe play an important role in consolidation
Reconsolidation is the process of returning information back to LTM after it has been retrieved and used – the memory may be altered in this time.
CONSOLIDATION – RATS IN A MAZE
HUDSPETH, MCCAUGHT & THOMPSON, 1964
The research The Results
Rats learned to run a maze to find a food reward
4 groupsA – ECT immediatelyB – ECT 20 seconds afterC – ECT 30 minutes afterD – ECT 60 minutes after
A – all rats forgot completely
B – partial recallC – partial recall
(better than B)D – total recall
Consolidation seems complete after about 1 hour
LINKING CONSOLIDATION THEORY & H.M It has been proposed that the hippocampus acts as a kind
of memory formation area where the brain temporarily holds & processes the components of the info to be remembered e.g. sounds, location, images etc.
All of these components of the information need to be integrated or linked together, in the hippocampus to form a single episodic memory.
After looking at the consolidation theory – the example of H.M.’s lack of new long term episodic or semantic memory formation suggests that the process of consideration was unable to occur because of the lack of coordination between the structures needed to make new memories.
OR
THINK …..THE HIPPO ON CAMPUS LIVES ON MEMORY LANE
DEEP WITHIN THE TEMPORAL LOBE- THE AMYGDALA Mediation of fear – sympathetic
arousal Seizures involving the amygdala
involve intense fear Damage leaves a person unable
to learn a fear response through classical conditioning
Involved in remembering the emotional significance of an event
Can effect the consolidation of memory – stimulation better recall, retardation poorer recall
Also concerned with learning.
READ BOX 6.10 ON P 341 BRAIN TRAUMA &
MEMORY LOSS – BOXING
LEARNING ACTIVITY 6. 29
Page 342 questions 1 – 6
Amnesia Amnesia refers to any form of memory loss
Can be partial or complete Can be temporary or permanent
Amnesia is usually caused by brain trauma (inflicted brain injury or acquired brain injury)
The severity of the injury determines the type and severity of the amnesia Usually experience a period of unconsciousness, followed
by a period of confusion, then the period of time ‘forgotten’ usually shrinks to only a few seconds of minutes directly after the moment of trauma
Experience of amnesia can vary from a few days to several weeks, but commonly disappears suddenly, often after a natural sleep.
Types of Amnesia① Anterograde amnesia
Loss of memory of experiences that occur after the brain trauma
Difficulty learning new information Can clearly recall events before the trauma Can retain new info in STM indefinitely as long as it is
rehearsed Problem lies in the transference of information from
STM into LTM Experienced by people with Korsakoff’s syndrome and
Alzheimer's disease Korsakaff’s syndrome (neurodegenerative disease) Acute inflammation and damage to hippocampus and
thalamus Often associated with chronic alcoholism and thiamine
deficiency
Types of Amnesia① R② Retrograde amnesia
Loss of memory of old info and experiences before the trauma occurred
Loss can extend back from moments to yearsUsually temporaryHowever, very common to permanently ‘lose’
the memory of the moment leading up to the trauma itself
This permanent loss is explained by the interruption of consolidation into LTM
LEARNING ACTIVITY 6. 31
P 347 QUESTIONS 1-6
THEN …
MOVIE ANALYSIS:MEMENTO/50 FIRST
DATES VS. THE BOURNE IDENTITY
Comment on how accurately the movie portrays the amnesia, include a psychological description
and explanation of the amnesia and the accuracy of these symptoms as depicted in the movie.
1 paragraph ONLY.
Dementia & Alzheimer’s Disease Dementia & Alzheimer's discussed in this study
design (for a full list FYI you can read box 6.12 for common types of dementia)
Common acquired brain injury is caused by neurodegenerative disease where brain tissue slowly deteriorates over time
Dementia Progressive decline in mental functioning Loss of mental capacity: decline in intellectual
ability, poor judgment, poor social skills and abnormal emotional reactions
Memory loss is persistent and progressive Not a normal part of ageing Comes in many different forms
Alzheimer’s D
isease Alzheimer’s disease
A form of dementia Physical break down of neurons causes plaques in the brain
– sections of neurons tightly bound together, causing gaps in other areas (only observable post-mortem) caused by high concentration of the protein amyloid in the brain (see next slide for Amy Loid!)
Often have low concentrations of neurotransmitter; acetylcholine
Affects around 100 000 people in Australia No accurate diagnostic tests available. Only accurately
diagnosed after death and brain tissue is examined for plaques
Memory loss, confusion, irritability and impaired decision-making are common symptoms
Memory loss is persistent and progressive Episodic memories are affected Forget words and names of people and commonly known facts Lose ability to follow directions of a story plot Lose ability to perform everyday skills
No cure, but can treat early stages with acetylcholine.
ALZHEIMER’S DISEASE: POST-MORTEM
So we know: Show high levels of the protein Amyloid Not usually in the brain Highly toxic – causes cell death Causes the development of the plaques
and tangles Brains also have a massive lack of
acetylcholine (an important neurotransmitter)
The rhyme:
LEARNING ACTIVITY 6. 33
Page 351 questions 1 – 3
Memory decline over the lifespan Memory decline is not an inevitable
consequence of ageing If it does decline, short-term memory and
explicit declarative memories (episodic and semantic) tend to be affected, rather than procedural memories
Aging and STM decline Info transmission in NS is generally less efficient
in older people (physical effects of ageing)The more complicated the task, the more STM
decline is evident in older peopleLess activity in areas of the frontal lobe
associated with STM when >60 years old
Memory decline over the lifespan Ageing and LTM decline
Episodic memories have been shown to start a steady decline as early as 30 years old
Procedural memories appear to remain intact over time
Semantic memories don’t appear to be affected much by age
However, older people don’t tend to encode new information in as much detail or as accurately as younger people – so often takes an older person longer to learn new things
Speed and fluency of retrieval also tends to decline with age
Decline in memory in older people is often explained by lack of motivation or more commonly, a lack of confidence
Recall of items is lower, but recognition of items is no different than younger people – use recognition tests, not recall
Memory decline can also be explain by cognitive slowing due to natural shrinkage of frontal lobes with age. Cognitive slowing affects all cognitive processes, not just memory
SO TO RECAP ….. Older people Do take longer to
learn new info
STM – depends on the task, easy one part tasks ok, tasks that require divided attention not so good. Recall down, Recognition same.
LTM - Episodic down, Procedural same, Semantic Same.
LEARNING ACTIVITY 6. 33
Page 351 questions 1 – 3
Chapter 6 Revision
True/False Quiz on page 355
Practice Test on page 356-360