
Take a minute to list all the things that our memory is useful for.

Now think about all the things that we wouldn’t be able to do if we did not have our memory.
-tying shoelaces
-remembering faces
-no friends
-no self-concept
-no personal identity


Human memory is not a single organ.

Technically we do not actually have a memory- we have different memory systems.

Memory consists of a collection of complex interconnected systems, each of which serves a different purpose and operates in a very different way.


Despite these differences, all memory systems have some functions in commonthey each receive, process and store information for future use.
 a) b)
When we receive sensory information the brain must select what information will be: attended to, processed and stored in the various memory systems eliminated and therefore not stored in memory.


If this process did not occur our memory systems would be overloaded with unimportant information.
Eg. The case study of ‘S’.


In terms of people who are said to have “lost” their memory- this is generally a reference to a situation where one or more memory systems have malfunctioned.

To have no memory at all you would probably be unconscious or dead.

Most psychologists view memory as an active information-processing system that receives, organises, stores and recovers information similar to the way a computer operates.


Like a computer, memory does not passively receive and store new information.

Instead, it actively alters and organises incoming information so that it can be stored in a way that is relatively easily retrieved.

Memory and a computer are also comparable in the way that they each deal with information in a sequence involving three key processes: encoding, or conversion of information into a useable form; its storage or retention after being encoded; and its recovery or retrieval when needed.


Information that is received and stored in memory must be converted from its raw sensory state to a form that the brain can process and use.

New information must also be placed, or represented, in some form- sound, visual image, touch or meaning- in the memory system.

The entire process of converting information into a useable form or code that can be stored in memory is called encoding.

Similar to transduction in visual perception.


Next, information must be retained by the information-processing system.

Storage is the retention of information over time.

Personal computers usually store information on a hard drive, whereas human memory stores information in the brain.


Finally, the information is retrieved, or located and taken out of storage when it is needed.



The retrieval of some information is very easy and quick, such as your name or birth date.

Other information is harder to retrieve such as something you learnt in year 7 science.

In these instances we often rely on cues to retrieve information that has been stored in memory.


Many models have been presented in trying to explain how memory works as a structure or construct that we rely on so much.

Some models have been more influential than others and continue to be studied and revisited by researchers to improve our understanding of memory.

-
-
-

Three models that we will study are:
Atkinson and Shiffrin’s (1968) multi-store
model which describes memory as having three components called the sensory register, the short term store and the long term store
Baddeley and Hitch’s (1974) model of
working memory, which changes views on the roles and functioning of short term memory
Craik and Lockhart’s (1972) levels of
processing framework which emphasises the importance of the ‘depth’ at which we process information.


American Psychologists Richard Atkinson and
Richard Shiffrin developed the first influential model of memory in 1968 called the multi-store model.

The Atkinson-Shiffrin multi-store model represents memory as consisting of three distinguishable components called the sensory register, the short-term store, and the long-term store. Each component, or store, represents a place where information is stored and processed.


Although these three memory systems are viewed as separate sub-systems of memory, they each operate simultaneously and interact in many ways.

Within each stage of memory, information processing involves encoding, storage and retrieval of information.


According to this model, when information is received from the environment, it passes from the sensory register to the short-term store and then to the long-term store.

Each stage of memory differs in terms of its
function (the role it plays), its capacity (the amount of information it can hold at any given moment) and its duration (the length of time it can hold information).


The sensory store is the entry point for new information into the memory system.

It stores vast quantities of information for a very brief period of time (milliseconds)

Anything that is not attended to in sensory memory is then lost.

If the information is attended to it is then passed on to the short-term store.





The short term store is described as a
‘temporary working memory’ in which we manipulate information that is held to perform everyday functions.
It holds the information that we are consciously aware of at any given time.
It receives information from the sensory register as well as retrieving previously stored information from your long term store.
It has a limited capacity and can only hold around 7 items of information at a time, and only for around 30 seconds unless a conscious effort is made to keep it there longer.

This is achieved through rehearsal.


The long term store holds information relatively permanently in a highly organised way and has an essentially unlimited capacity.

It does not usually decay and can be stored for a lifetime.

We can however find it difficult to retrieve information if we use ineffective search strategies or by failing to use the correct memory trace.

This can also be caused by interference.


An important feature of the model is its description of memory in terms of it structural
features and its control processes.

Structural features are the permanent, built-in, fixed features of memory that do not vary from one situation to another.

Eg. The three different stores, the function of each store, the capacity and duration of each store.


Control processes are selected and used by each individual and may vary across different situations.

They are under the ‘conscious’ control of the individual and which process is used depends on the particular person.

Eg. Whether the individual attends to the information, whether they rehearse the information and the search strategies that they use.


Given the time that has passed since the evolution of the multi-store model, psychologists have built on and reconsidered many components of Atkinson and Shiffrin’s work.

This lead to the study of the three memory systems in more detail and their name changes to sensory memory, short-term memory and long-term memory.


Sensory memory is the entry point of memory-the initial stage of the memory system in which all of the stimuli that bombard our senses are retained in their original sensory form (not encoded) for a very brief time.

It is assumed to be unlimited in capacity.


An important function of sensory memory is that it stores sensory impressions long enough for them to slightly overlap one another. (Waving a pen in front of your face).

This means that we see the world as continuous and not as a series of disconnected visual images or sounds.

Sensory information remains in sensory memory just long enough for it to be attended to and selected to be transferred to short-term memory
(STM).


We are not consciously aware of the majority of information that enters our sensory memory.

However when we direct our attention to it in order to store it in STM we become consciously aware of it.

Incoming sensory information is stored in separate sub-systems called sensory registers and it is believed that there is a separate sensory register for each of the senses.


Iconic Memory is the name given to visual sensory memory, or the memory of visual sensory information.

Visual images in their original sensory form are usually retained in iconic memory for one-third of a second.

Sperling’s experiment.


Used a tachistoscope to briefly present 12 letters to participants.

The participants were asked to verbally report as many letters as they could recall.

Most could recall only 4 or 5 but reported seeing all of the letters for a brief second.

He then extended his research into using a tone to measure how long the image was stored.


Some people are able to remember highly detailed scenes as if the actual event were occurring before them.

These people are said to have eidetic memory. These memories are said to be an exact replica of a visual image that persists over time without distortion.

These can last sometimes for days or weeks.


View this image for 30 seconds and then answer the following questions.

1.
2.
5.
6.
3.
4.
How many bows are on the girls apron?
Is the hemline of the girl’s dress above or below her knees?
How many flowers are in bloom on the taller plant?
How many whiskers are there on the cat in the tree?
How many stripes are on the cat’s tail?
What is the girl wearing in her hair?


Echoic Memory is the name given to auditory sensory information, or the memory of auditory sensory information.

It is called echoic memory because the sounds linger in it like an echo.

Echoic memory stores information for longer than iconic memory.

Iconic (visual)
Memory
About 0.2-0.4 seconds
Echoic (auditory)
Memory
About 3-4 seconds


The availability of this information for 3-4 seconds is generally long enough to select what has been heard for further processing and interpretation before the sound disappears completely.

Auditory information must also be held for long enough for all parts of speech within a list of words to be identified.


Short-term memory (STM) is a memory system with a limited storage capacity in which information is stored for a relatively short period of time (unless renewed in some way).

STM stores information temporarily but for a longer time than sensory memory.

In short term memory the information is no longer an exact replica of the original sensory stimulus, but an encoding of one.


Generally items in STM can be retained fairly well for the first few seconds.

After 12 seconds, recall begins to decline and by about 18 seconds almost all of the information disappears entirely if it has not been renewed in some way.

Information can be renewed in STM and retained for longer through use or by constantly repeating it.


Compared to sensory memory and long-term memory, STM is very limited in storage capacity.

If you have an average storage capacity you should be able to recall around seven numbers in a row. If you were given eleven numbers this would not be quite as easy.

The limited capacity of seven bits of information in short-term memory was first described by George
Miller in 1956.

 http://faculty.washington.edu/chudler/stm0
.html


Millers research indicated that STM has a capacity of holding between five and nine units of information at any one time.

7 + 2

Rarely are we able to hold any more than 7
+ 2 pieces of information in STM regardless of what type of information it is.

Information stored in STM is lost primarily through decay (not being used) and
displacement (being pushed out) by new information.


Many psychologists prefer to use the term working memory rather than STM.

Working memory is the active part of memory where information you are consciously aware of is actively ‘worked’ on.


Working memory works on information from sensory memory and LTM.

Information from sensory memory is processed in working memory and information is extracted from
LTM to be used and manipulated in working memory.
-
-
-
-
Imagining
Problem-solving
Analysing
Reasoning
-
-
Comprehending
Planning all involve working memory.


Your working memory enables you to read by holding words from the beginning of a sentence while you continue to process the rest of the sentence.

If you were to work out a maths problem in your head you would be using working memory.


We can get around the limited capacity of shortterm memory.

One way is to learn the information well enough to transfer it to long term memory, which has an unlimited storage capacity.

Another way is to put more information into each of the 7 + 2 units that can be stored in STM.

D N V R C E W V D C S V

NSW VCR VCE DVD

People are usually able to recall more of the second set of letters even though it is made up of exactly the same letters.

This is a demonstration of chunking.


Chunking is the grouping or packing of separate bits of information into a larger single unit or
‘chunk’ of information.

Chunks can be take many forms. They can be numbers, images, words, sentences, phrases or abbreviations. (BHP, RACV, CSIRO).

Phone numbers

Car registration number plates


Rehearsal is the process of actively manipulating information so that it can be retained in memory.

There are two types of rehearsal:
-
-
Maintenance rehearsal
Elaborative rehearsal


Maintenance rehearsal involves repeating the information being remembered over and over again to retain it in short term memory.

When you hear something for the first time and go over it and over it so that you don’t forget it, you are using maintenance rehearsal.

Maintenance rehearsal can be verbal, which involves the use of words. It can also be non-verbal, involving visual or spatial information.


When the information is verbal, maintenance rehearsal can occur vocally, by saying the information aloud over and over; or sub-vocally, by silently repeating the information in your head.

Whether maintenance rehearsal is verbal, visual or spatial, provided it is not interrupted, information can be retained indefinitely in STM.

This does not necessarily mean that this information will automatically be transferred into
LTM.

When information is continually renewed in STM through the rehearsal process, the amount of new information that can enter is restricted because of the limited capacity of STM.


Elaborative rehearsal generally involves organising and dealing with new information in terms of its meaning.

Elaborative rehearsal is the process of linking new information in a meaningful way with information already stored in memory or with other new information, to aid in its storage and retrieval from long term memory.


Elaborative rehearsal is a more active process than maintenance rehearsal.

It is also more effective than maintenance rehearsal as it helps to ensure that information is encoded well.

When we relate new information to personal experiences and our personal situation, encoding is enhanced and therefore we are more likely to remember it. This is called the self-reference effect.







Elaborative rehearsal has a number of practical applications for students. The learning of new information is more likely to be retained in LTM when you:
Think about what the new information means
Ask questions about the new information
Link new information to previously learned information
Create visual images relevant to the new information
Link the new information to personal experiences or your personal situation.


In 1974 British psychologists Allan Baddeley and Graham Hitch developed a multicomponent model of memory.

Baddeley and Hitch’s model of working
memory describes the structure and function of working memory in terms of three components called the phonological loop, the visuo-spatial sketchpad and the central executive.

The three components are separate and can function independently but also interact.

-
-
-


Baddeley and Hitch were interested in studying working memory as a system that supports and enables complex and important cognitive abilities which they felt it had not yet been considered as.
Baddeley and Hitch proposed that memory consisted of:
One system for verbal memory
Another for visual information
And a central executive that processes the information from the other two sub-systems.


Think of your house. How many doors does it have in it?

In working this out, you probably formed some sort of visual image of your house. This relies on the sub-system specialised for visual and spatial information. You probably then counted the doors verbally using the sub-system specialised for verbal information. Finally, throughout this process there was a need for your central executive to select the strategy to complete the task, to manage the activities of the other two sub-systems and to control the whole process.

-



Verbal working memory (also called phonological
loop) stores a limited number of sounds
(phonemes), such as words, for a short period of time.
It encodes and stores auditory information and is active whenever you read, listen, speak or repeat words to yourself in order to remember them.
Our use of internal, unspoken speech during rehearsal is a crucial feature of the phonological loop and verbal working memory.
If we do not do this it becomes impossible to store verbal information.


Visual working memory (also called the visuospatial sketchpad) temporarily stores visual information, such as the location and nature of objects in the environment.

Visual information is anything that you can see or visualise, including features of the image.

Spatial information refers to the location of objects in space.

If you closed your eyes to visualise what the room looks like you would be relying on the visuo-spatial sketchpad.


Eg. Imagine a 4x4 grid in your head (16 squares).
Next imagine the number 1 in the square that is in the second column of the second row. Then put a two to the right of that. Then, in the square above the two, put a 3, and to the right of that put a 4,
Below the 4, put a 5, and below that a 6, and then to the left of that a 7.

What number is immediately above the 7?

To answer this you had to use your visuo-spatial sketchpad.


The central executive controls attention; integrates information from the verbal and visual storage systems, as well as information received from long-term memory; and coordinates the flow of information between the working memory and
LTM.

It works on the information from the other two subsystems.

This makes it the working part of working memory.

-

The central executive has a role in:
Directing your attention to activities you are currently undertaking
-
-
-
Filters essential from non-essential information
Combines information from the other two components
Selects, deletes and reorders information
-
Adds information when required from LTM to guide mental processes and behaviour.
Does not store information.


According to Baddeley a major problem with the theory he developed with Hitch is that it does not explain how working memory links with LTM.

In 2000 Baddeley added a fourth component called the episodic buffer.

The episodic buffer is a sub-system of working memory that enables the different components of working memory to interact with LTM.


The episodic buffer is assumed to be a limited-capacity temporary storage system that holds about 4 chunks of information.

It can hold any type of information and therefore works to integrate information from the other storage systems.

The episodic buffer is directly linked to LTM and it is separate and has its own storage space and processes for storing information.

It combines information into scenes or
‘episodes’ and allows them to be ‘buffed’ or worked on.


Long-term memory is the relatively permanent memory system that holds vast amounts of information for a long period of time.

It is a different kind of memory system to STM mostly because STM is active and LTM is inactive.

LTM differs from STM in several ways: how information is retrieved, the form in which information is stored and the way in which information is forgotten.


LTM has to be organised in a way that enables the efficient retrieval of information.

We retrieve information from LTM using retrieval cues. This can be intentional or unintentional.

In either case, only the specific information relevant to the cue is retrieved rather than the entire contents of LTM.

Remarkably it takes only a few seconds to search through this huge storehouse of information to find the information required.


Information retrieved from LTM is held in working memory while it is being used. Once it is no longer required, it can be returned into LTM for further storage.

If we are unable to retrieve specific information from LTM, it is because of poor organisation of the information during encoding and storage or failure to use the appropriate retrieval cue.

If information is not properly stored it is difficult to locate and retrieve.


STM stores information in terms of the physical qualities of an experience, especially sounds.

In contrast, LTM stores information semantically, that is in terms of its meaning.

In terms of forgetting, LTM differs from STM in that it does not only last longer but it is in fact permanent.

This means that forgetting occurs in LTM not because the memory is gone, but because we are unable to retrieve it.


Psychologists have distinguished between two types of LTM storage, each with distinctly different properties.

These are procedural memory and declarative memory. Two types of declarative memory have also been described. They are called episodic memory and semantic memory.


Procedural memory is the memory of actions and skills that have been learned previously and involves knowing ‘how to do something’.



How to drive a car
How to ride a bike
How to use a computer
Procedural memories are also called implicit memories because the information can be retrieved through performance rather than intentional conscious recall or recognition.
It can be difficult to put procedural memories into words.


Declarative memory is the memory of specific facts or events that can be brought consciously to mind and explicitly stated or ‘declared’.

Consequently declarative memories are also called
explicit memories.

Identifying a type of flower

Explaining a statistics formula

Describing the events of a movie you have seen


When distinguishing between declarative and procedural memory psychologists often refer to declarative memory as involving ‘knowing what’ and procedural memory as ‘knowing how’.


Episodic memory is the declarative memory system that holds information about specific events or personal experiences.

Like a mental diary, recording the autobiographical episodes we experience.

What you ate for breakfast

The birth of a brother or sister

Going to the dentist


Semantic memory is the declarative memory system that stores the information that we have about the world.

It includes our specialised knowledge in areas of expertise, academic knowledge of the kind learned in school, rules, everyday general knowledge, the meaning of words.

Semantic memories seem to involve facts that do not depend on a particular place or time but are simply facts.


It could be argued that episodic and semantic memories go hand in hand with each other in that when we are storing a semantic memory we would also have episodic memories being stored alongside that.


Fergus Craik and Robert Lockhart were the first influential psychologists to argue against the concept that memory has a specific structure that can be divided into sections.

They proposed a conceptual framework of memory which emphasized the importance of the level at which new information is processed.


Craik and Lockhart’s levels of processing
framework proposes that the level, or depth, at which we process information during learning determines how well it will be stored in LTM.

They proposed that memories are best encoded, organised and stored in LTM by meaning.

However, processing meaning is not a matter of meaning or no meaning.

Instead there is a continuum ranging from shallow to deep processing.


Information processed at the shallow level will be held only briefly whereas information processed at a deeper level will be held for much longer.

Elaborative (deep) vs maintenance (shallow) rehearsal.

Self-referencing involves deeper processing.


A sample question from the research conducted:

1) required semantic processing
2) required acoustic processing
3) required visual processing
Which type of processing would be most effective?
1.
2.
3.
Semantic
Acoustic
Visual


One problem with this theory is that the level of depth is difficult to measure.

It is accepted however, that deeper levels of processing lead to more effective encoding and therefore retrieval.


One of LTM’s most distinctive features is its organisation of information. The task of retrieving information from LTM is very different to retrieving information from STM.

In STM there is only a choice of 7 + 2 pieces of information to choose from, however LTM stores such a vast amount of information that there is a need for some form of information to assist the storage and retrieval process.


Research has found that information stored in LTM is organised in meaningful clusters of related categories.

Eg. Fruit types, names, occupations.

Research findings also indicate that information is also linked or associated with other information stored in LTM.

There is also considerable research evidence that suggests that recall from LTM is better when we further organise the information stored there.

Bower and Clark experiment.


Information in LTM is both organised and associated with other information held in the LTM system. The semantic network theory is one theory that describes how this is done.

Semantic network theory proposes that information in LTM is organised systematically in the form of overlapping networks or grids of concepts that are interconnected and interrelated by meaningful links.


According to this model, each concept, called a node is linked with a number of other nodes.

This means that when we retrieve information, the activation of one node causes other related nodes to be activated also.

In reality, LTM contains thousands of concepts, each with very many connections.

This system of storing information in terms of meaning is quite an effective means of storage which enables effective and efficient retrieval of information.

According to the semantic network theory:
 retrieval begins with someone searching a particular region
 then tracing associations for links among memories in that region, rather than randomly searching the vast information stores in LTM.

It also proposes that a specific retrieval cue activates relevant nodes, which in turn activate other nodes to which they are linked.


The shorter the link between nodes the stronger the association, the less time it takes to activate related concepts to which they are linked.

The longer the link between nodes the weaker the association between them and the longer it takes to activate the information that is further away.

The more nodes that are activated, the quicker the retrieval of information from
LTM.


To test whether STM is a separate sub-system of memory from LTM, psychologists have studied people’s memory of lists of words, numbers and other information.

A consistent finding has occurred: which words are recalled from the list tends to depend on their serial position in the list.


The Serial Position Effect is a research finding that suggests that recall is better for items at the end and beginning of the list than for items in the middle of the list.

The Primacy Effect describes superior recall of items at the beginning of a list.

The Recency Effect describes superior recall of items at the end of a list.

Together with the relatively low recall of items from the middle of the list, this pattern makes up the serial position effect.


The most acceptable explanation relates to differences between STM and LTM.

If recall occurs immediately after learning, the last few items are remembered first because they are still in STM.

The first few items are remembered most because the received more attention and rehearsal than other items and are therefore transferred into LTM.




Items around the middle of the list are presented too late to be adequately rehearsed and transferred into LTM and too early to be held in STM without rehearsal and are therefore likely to be forgotten.
If participants are asked to recall the list 30 seconds after learning, the serial position effect is not as prominent as this goes beyond the limits of STM.
This also works in real life settings such as with advertisements.


Memories are not stored in any one location.

They are stored throughout the brain and linked together via neural tracts.

This does not mean all areas of the brain are equally involved.

Different areas are active when we encode, store and retrieve different types of information.


Most relevant research conducted by Eric Richard
Kandel.

He identified changes in the structure and functioning of the neurons in the brain when forming a new memory. He experimented on a species of large sea slugs found in California called
Aplysia californica.

He did this because these animals have a very simple nervous system structure.


They also have some of the largest neurons in the animal kingdom.

This means they can be easily observed and stimulated.

Read experiment page 335.

According to Kandel, when these animals acquire a new memory through repeated stimulation, significant changes occur in neurons involved in the process.

Draw neuron.


The more the neurons in a circuit are activated through use, the easier it becomes for information to travel through the circuit.

In sum, Kandel’s research indicated that any experience that results in memory produces physical changes in the brain at the neuronal level, strengthening connection between neurons and making communication easier the next time.


In short term memories there is only an increase in neurotransmitter.

In long term memory all changes occur.

Each time the memory is recalled the neurons in this circuit are activated.

Why is the Kandel research difficult to generalise?


Just above the ear and about 4cm straight into the brain is the hippocampus.

The hippocampus is tubular and curved.
Humans have two, one in the temporal lobe of each hemisphere.

In 1957 a study highlighted the importance of the hippocampus in memory.

Ream HM’s story page 338.

-

This case highlighted the role of the hippocampus in memory as:
Being involved in the formation of new longterm memories, but not a storage site for longterm memories.
-
Encoding new declarative (semantic and episodic) memories but not really procedural memories.

Damage does not effect formation or retrieval of procedural memories but does effect declarative memories.

Does not effect STM.

-
-
-

Why was HM able to remember old experiences but not able to remember any new ones?
The hippocampus acts as a memory formation area where the brain temporarily holds and processes components of the information to be remembered.
An episodic memory will have different components which need to be integrated to form a single memory.
When the memory is formed the different components will transfer to the cortical areas of the brain specialised in that component of the memory (eg. Location- parietal lobe)




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Consolidation theory proposes that physical changes to the neurons in the brain occur when something new is being learned, and immediately following learning.
These changes occur for a period of time after learning takes place.
This theory also proposes that if memory is disrupted during the consolidation phase, information may not be processed in LTM and will therefore be lost.
If disruption does not occur the information becomes a permanent part of LTM until it is retrieved.
Consolidation is a gradual process and the material is vulnerable to disruption for up to 30 minutes.

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It is believed that the hippocampus and medial temporal lobe in each lobe play an important role in the consolidation process.
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In HM’s case it is suggested that he could not form new LTM’s because the part of the brain used for consolidation had been removed.
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Evidence comes from people who have experienced brain trauma, been knocked unconscious, acquired certain diseases, or received electroconvulsive shock therapy.

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Other research has come from animal research involving rats.
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Administered ECT to rats at intervals of:
Group A- immediately after running the maze (none remembered)
Group B- 20 seconds after (partial)
Group C- 30 minutes later (partial but better than
B)
Group D- 60 minutes after (complete recognition)

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It has also been proposed that after a memory is activated from LTM, it needs to be reconsolidated to be stored back in LTM.
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This is called reconsolidation.
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This means that when we use an old memory we can alter it, or adjust it with the new memories formed before it is reconsolidated. This allows us to build on the old memories.

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Many causes of memory failure are caused by damage or injury to the brain.
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The term brain trauma is an ‘umbrella’ term that is used to refer to any brain damage that impairs the normal functioning of the brain, either temporarily or permanently.
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It could be inflicted (intentional blow or seizure) or acquired (stroke or brain disease).

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A neurodegenerative disease is a disease characterised by a progressive decline in the structure, activity and function of brain tissue.
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The neurons within the brain tissue gradually become damaged and lose their function.
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This decline is usually age-related.

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Memory loss due to any reason is called amnesia.
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The term amnesia is used to refer to loss of memory, either partial or complete, temporary or permanent.
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Any brain trauma typically results in amnesia.
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The severity of the injury determines the specific characteristics of the amnesia.
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Often the period of lost memory will return over time leaving only a small window unaccounted for.

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There are many different kinds of amnesia, each with a different pattern of symptoms.
Some examples are:
Amnesia for the meaning of nouns but not verbs
Amnesia for animals and not people
Amnesia for human faces but not other objects
Difficulty using STM or forming new LTM’s
Difficulty retrieving information from LTM
The two we will look at are anterograde

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If brain damage causes loss of memory only for information or events experienced after the person experiences brain damage, it is called anterograde
amnesia (A for after).
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In general any information from before the brain injury remains.
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They are not able to remember what has happened since the brain injury.

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Anterograde amnesia is one of the symptoms experienced by people with Alzheimer’s disease or
Korsakoff’s syndrome.
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Korsakoff’s syndrome is a neurodegenerative disease involving severe memory disorders associated with damage to brain structures and areas involved with memory, such as the hippocampus and thalamus.

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This disease occurs mostly in chronic or long-term alcoholics.
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It is linked to the prolonged loss of vitamin B in the diet and alcoholics often have this deficiency.
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Although this disease is considered to be neurodegenerative symptoms can often appear in just days.
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A person with this disease can appear quite normal in terms of appearance, IQ, alertness, motivation etc

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An inability to remember information that was acquired before brain damage is called retrograde
amnesia. (Retro refers to backward, and refers to memory loss that goes back in time).
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The extent of retrograde amnesia varies greatly, ranging from moments to days, weeks or even years.
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The amount of time over which memories are affected is often related to the severity of the damage to the brain.

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In most cases resulting from a brain injury, there is some recovery of the lost memories- usually with memory for older events recovering first.
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However, there always seems to be a period – usually just prior to the time when the brain injury occurred- for which there is no recovery of memory, and the amnesia is absolute.
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In cases that are as a result of other damage to the brain, such as Alzheimer’s disease, the extent of the amnesia is often not clearly defined and the recovery of the lost memories is rare.

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The information processing model of memory explains retrograde amnesia in terms of an interruption to the consolidation of the memory trace.
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In the period of time just prior to the brain trauma, a memory trace was forming as information was being processed from STM to LTM.
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At the point of the trauma, the consolidation process was interrupted and therefore the memory of information just prior to the injury will not be consolidated and therefore lost forever.

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Dementia is a general term that describes the symptoms of a variety of brain illnesses that progressively kill brain cells and result in irreversible structural and chemical changes in the brain that lead to permanent and severe cognitive loss.

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Loss of mental capacity
Memory loss
Decline in intellectual ability
Poor judgment
Poor social skills
Abnormal emotional reactions

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It progresses in stages with memory loss being the first sign and all symptoms worsen as ageing progresses.
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In the final stage people with dementia are completely shut out of their world.
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The most common form of dementia is Alzheimer’s disease.

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Alzheimer’s disease is a neurodegenerative disease characterised by the gradual widespread degeneration of brain neurons, causing memory loss, a decline in cognitive and social skills, and personality changes.
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It is the fourth largest cause of death in
Australia.
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Postmortems of people who have had
Alzheimer’s shows that the brain appears to have rusted, deposits of plaque bound together like blobs and there are visible tangles of brain fibre.

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It is estimated that the disease affects:
1 in 25 over 50
1 in 8 over 65
1 in 4 over 80
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It also affects some people in their 50’s.
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An accurate diagnosis of this disease can only be made after death when an autopsy can be done.
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Diagnosis can be difficult as there is no one symptom that is reliable.

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Memory loss will include:
Events
Words or names
Written and verbal directions
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Stories on TV, in movies or books
Stored knowledge
Everyday skills
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Severe personality changes are also observed in patients with Alzheimer’s.

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In the latter stages of Alzheimer’s patients will struggle to undertake even the simplest everyday tasks.
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They may become unable to remember their own family members and eventually forget their own identity.
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The thing that distinguishes Alzheimer’s from other diseases is that it includes both loss of past memories (retrograde) and difficulties retaining new information (anterograde).

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Autopsies reveal high levels of the protein amyloid in the brains of people with Alzheimer’s.
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This is not usually found in the brain and is toxic, poisoning the brain cells.
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It causes abnormal structures to form called
plaques and tangles.
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Plaques are dense deposits of protein outside the neuron and tangles are twisted fibres that build up around the neuron.
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The area of the brain most affected is the hippocampus.

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There is currently no cure for Alzheimer’s disease, however some medications can slow the progression.

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Most people believe that memory decline is a natural part of ageing.
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Research shows however, that although there is some natural decline in memory with age, memory is not an inevitable consequence of ageing.
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If a decline in memory is experienced through ageing, effects are more likely to be experienced in working memory and the declarative memory systems (episodic and semantic memories) than in procedural memories.

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The impact of age on STM seems to depend on the nature of the task.
If the task is simple it should not be affected by age.
If the task is more complex, age related factors may impact on effective STM functioning.
One study shows that when storage and manipulation of information is required younger participants scored higher (3.2 words out of a list) than their older counterparts (1.7 words out of a list)
Neuroimaging studies have shown that beyond 60 years of age, there is a decrease in the activation of areas of the frontal lobes of the brain believed to be involved in STM.

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Research findings indicate that some LTM stores are more likely to be affected by age than others.
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Episodic memory is the most likely to decline with age and this decline can start as early as 30 or as late as 50.
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Although many semantic and procedural memories are not easily lost, older people take longer to learn new information and skills.

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It seems that older people do not encode new information with as much detail or as precisely as young people.
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The speed and fluency of retrieval of information from semantic memory is particularly prone to decline.
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One explanation for this is lack of motivation.
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There is however less age-related decline for memory tasks in which a person is motivated to remember something. Eg. Taking a cake out of the oven.

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A second explanation is that as people get older they tend to lose confidence in their memory.
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A third explanation is that the inability of some older people to access information from LTM may be more to do with the kind of measure of retention used that with their age.

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The most common reason is a process called
cognitive slowing. This refers to the slowing of
Central Nervous System functioning and the inability to effectively process information the way a person may once have.
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This occurs because the frontal lobe shrinks as age progresses and therefore cognitive function is influenced by this process.