1. Memory IV Memory Systems Amnesia

2. Are there multiple LTM memory systems?
How do you learn a new skill?
How do you learn a new fact?
How about learning about an event?
Is there one long-term memory (LTM) system for these types of knowledge or are there multiple LTM systems?
Long-term memory, information that is acquired in the course of an experience and that persists so that it can memory can be consciously retrieved, so that we can use our remembrance of things past to guide present thought and action.
By contrast, other forms of long-term memory influence our present thinking and behavior while operating outside awareness.

3. A Taxonomy of Memory Systems
LONG TERM MEMORY
EXPLICIT
(declarative)
IMPLICIT
(non-declarative)
SEMANTIC
(facts)
EPISODIC
(events)
PRIMING
(perceptual,
conceptual)
PROCEDURAL
(skills & habits)
ASSOCIATIVE
LEARNING
(classical & operant conditioning)
Theorists believe that there are multiple forms of long-term memory that differ in their basic information processing properties and in the brain structures that support them. These various forms of memory are thought to fall into two general classes, described as declarative and nondeclarative.
Declarative memory (also known as explicit memory) refers to forms of long-term memory that can ordinarily be consciously recollected and “declared,” or described to other people, such as memory for facts, ideas, and events. Declarative memory encompasses episodic memory, the memory of events in our own personal past, and semantic memory, our general knowledge about things in the world and their meaning, a distinction proposed by Endel Tulving in Tulving defined episodic memory as the conscious knowledge of temporally dated, spatially located, and personally experienced events or episodes.
Tests that assess declarative memory are termed explicit memory tests because they require the retrieval of an explicit description or report of knowledge from memory. Declarative memory is highly flexible, involving the association of multiple pieces of information into a unified memory representation; thus, we may have different routes to retrieval of a given memory. Both forms of declarative memory, episodic and semantic, depend on the operation of the medial temporal lobes.
Semantic memories are memories for facts; meaning-based memory. They are explicit, and thus declarative. For instance, you may be able to state, “I know the first president of the United States was George Washington.” Episodic memories are memories for specific events of “episodes” in time. They, too, are explicit, and often involve personally-experienced events. For instance, you may remember the first roller coaster experience you had, or your first kiss. With episodic memories, you should be able to recollect the details revolving around that particular event.
Procedural memories are skill-based memories. They involve knowledge of “how to” do things. Procedural memories begin as explicit, but with practice and experience, become implicit. For instance, when you first learned to ride a bike, you had to watch the sidewalk, watch your hands, watch your feet. You had to balance your body and the bike, and think about which foot was cycling; left then right. You had to steer the handlebars. You had a lot on your mind and your body was involved in many simultaneous tasks. Each part of this task was explicit (you had to pay attention to and consciously monitor). Then, with practice, the task of riding your bike became easier. Over time, you no longer had to think about your feet, or focus on balancing. You didn’t have to think about it at all. The memory, with practice, became implicit. You don’t recollect the details, now, in how to ride a bike, you just “do it”. The same could be said about how to drive a car (remember all the training you had to go through and how you had to recall and think about each detail!); not any more. When someone asks you “how to drive a car”, it is difficult for you to explain explicitly, because the memory has become implicit.
Medial Temporal Lobe
Cortex
Striatum
Amydala/ Cerebellum

4. Semantic and Episodic Memory
Semantic memory
memory for facts about the world
can a canary sing?
who is Secretary of State of the US?
Episodic memory
memory for events in our lives (temporal organization)
what did you eat for breakfast?
where were you for the Super Bowl game?
EPISODIC MEMORY:
Memory tied to your own personal experiences
Examples:
What did you have for lunch?
Did you go to discussion section this week?
Have you met any movie stars?
Why are these explicit memories?
Because you can actively declare your answers to these questions
SEMANTIC MEMORY
Memory not tied to personal events
General facts and definitions about the world
who was George Washington?
what is a cloud?
what date does Independence Day fall on?
These are explicit memories because you can describe what you know about them
These are not always easy to distinguish. Facts about the world are learned through experience. E.g., you might remember learning in the news about the new secretary of state.

5. Semantic or Episodic Memory?
I remember that
I got soaked in the rain yesterday walking to class
Barack Obama is the President of the US
my first grade teacher could not pronounce my name the first day of school
California is facing severe drought conditions

6. Implicit and explicit memory
Implicit memory:
past experiences influence perceptions, thoughts & actions without awareness that any information from past is accessed
Explicit memory:
conscious access to info from the past
(“I remember that..” )
-> involves conscious recollection
There are two general classifications of long-term memories. They include explicit and implicit types of memory. Explicit memories involve direct awareness. They are declarative; one can talk about the details of explicit memories and discuss them as fact. In comparison, implicit memories evolve outside of awareness, and cannot be consciously recalled. We only know they occur by observing changes in behavior.

7. Explicit & Implicit Memory Tests
Look at the following words. I will test your memory for these words in various ways.

9. Memory Test Explicit test of memory: recall
Write down the words you remember from the list in the earlier slide
Implicit tests of memory
On the next slide, you will see some words missing letters, some “word fragments” and some anagrams. Guess what each word might be.

11. Implicit Memory Tasks
Word-fragment completion is an implicit memory task. Fragments are (often) completed with words previously studied in the absence of an explicit instruction to remember the word
Amnesiacs often show spared implicit memory
dissociation suggest different systems for implicit and explicit memory systems

12. Implicit vs. Explicit Memory
Graf, Squire, & Mandler (1984):
Study words: cheese, house, …
Explicit memory test: cued recall. Complete fragment to a word from study list:
ch _ _ _ _
Implicit memory test: word stem completion. Complete fragment to form any word: ch _ _ _ _
complete it with the first word that comes to mind

13. Word-stem completion spared in amnesiacs
Why are amnesiacs better at word stem completion? It depends on how word stem completion is scored perhaps? Maybe the researchers counted only the study words as correct – and control subjects thought they were supposed to stay away from the study words and pick a non-studied word??
Graf et al. (1984).

14. Implicit Memory Other forms Procedural Memory Perceptual learning
Classical conditioning
Real-world applications
Unintentional plagiarism
Novel password/key systems
Procedural memory:
Memory that enables you to perform specific learned skills or habitual responses
Examples:
Riding a bike
Speaking grammatically
Tying your shoes
Why are procedural memories implicit?
Can’t readily describe their contents
They are automatically retrieved when appropriate
Implicit memory refers to using stored information without trying to retrieve it. People often retain and use prior experiences without realizing it. For example, suppose that the word serendipity is not part of your normal working vocabulary, and one day you hear the word used in a conversation. A day later you find yourself using the word in conversation and wonder why. The earlier exposure to the word primed you to retrieve it automatically in the right situation without intending to do so.
Another example of implicit memory in everyday life is unintentional plagiarism. That is, people can copy the ideas of others without being aware they are doing so. The most famous case involved British singer-songwriter George Harrison, formerly of the Beatles. Harrison was sued because his 1970 hit song “My Sweet Lord” sounded strikingly similar to “He’s So Fine,” a 1963 hit by The Chiffons. Harrison denied that he had intentionally copied the earlier song but admitted that he had heard it before writing “My Sweet Lord.” In 1976 a judge ruled against Harrison, concluding that the singer had been unconsciously influenced by his memory.

15. Password systems based on implicit learning
Current passwords need to be explicitly remembered
Can a secret password be planted in somebody’s mind without them being aware of it?
Researchers* developed a “Brain Authentication” system based on Guitar Hero
Participants learn over 45 minutes to play a random 30 letter sequence that represents a “password”
Participants appear unable to reconstruct the trained sequence
Authentication then requires participants to play their 30 letter sequence better than some other random 30-letter sequence
A cross-disciplinary team of US neuroscientists and cryptographers have developed a password/passkey system that removes the weakest link in any security system: the human user. It's ingenious: The system still requires that you enter a password, but at no point do you actually remember the password, meaning it can't be written down and it can't be obtained via coercion or torture -- i.e. rubber-hose cryptanalysis. The system, devised by Hristo Bojinov of Stanford University and friends from Northwestern and SRI, relies on implicit learning, a process by which you absorb new information -- but you're completely unaware that you've actually learned anything; a bit like learning to ride a bike. The process of learning the password (or cryptographic key) involves the use of a specially crafted computer game that, funnily enough, resembles Guitar Hero. Their experimental results suggest that, after a 45 minute learning session, the 30-letter password is firmly implanted in your subconscious brain. Authentication requires that you play a round of the game -- but this time, your 30-letter sequence is interspersed with other random 30-letter sequences. To pass authentication, you must reliably perform better on your sequence. Even after two weeks, it seems you are still able to recall this sequence.
Training is done using a computer game that results in implicit learning of a specific sequence of key strokes that functions as an authentication password. In our experiments, training sessions last approximately 30 to 45 minutes and participants learn a random password that has about 38 bits of entropy. We conducted experiments to show that after training, participants cannot reconstruct the trained sequence and cannot even recognize short fragments of it
By exhibiting reliably better performance on the trained elements compared to untrained, the participant validates his or her identity within 5 to 6 minutes. An attacker who does not know the trained sequence cannot exhibit the user’s performance characteristics measured at the end of training. Note that the authentication procedure is an interactive game in which the server knows the participant’s secret training sequence and uses it to authenticate the participant *

16. Amnesia

17. Amnesia Types: Retrograde: cannot remember old* memories
Anterograde: cannot form new episodic memories
*old = memories before injury

18. Sources Blow to head, Concussion
Korsakoff syndrome (severe vit. B1 deficiency)
Alzheimer’s
Damage to hippocampus, thalamic structures
ECT (electroconvulsive shock therapy)
Midazolam: artifically induced amnesia
Chronic alcoholism often leads to a thiamine (vitamin B1) deficiency in the brain, causing Korsakoff's syndrome, a neurological disorder.
Vitamin Thiamine  Vitamin B1
The anterograde amnesia property of midazolam is useful for premedication before surgery to inhibit unpleasant memories
Midazolam is among about 35 benzodiazepines which are currently used medically

19. Retrograde amnesia Temporal gradient:
early memories are better remembered than memories before trauma (Ribot’s law)
Recently formed memories continue to undergo neurological change: memory consolidation
Does not affect overlearned information (e.g. skills)
Retrograde amnesia often becomes less severe over time
Most remote memories are likely to return first

20. Temporal Gradient
Testing memory for diary entries from retrograde amnesiac
(Butters & Cermak, 1986)

21. Anterograde Amnesia Inability to acquire new information
Think of movie “memento”
Does not affect short-term memory
Does not affect general knowledge from the past
But, it is difficult to learn new facts
Affects memory regardless of modality (visual, auditory, tactile, etc).
Spares skilled performance

22. Famous Anterograde Amnesiac: HM
Surgery when 27 years old (1953) to deal with severe epilepsy
Removed bilaterally medial temporal lobes, including hippocampus
A NPR segment on HM
His case played a very important role in the development of theories that explain the link between brain function and memory, and in the development of cognitive neuropsychology, a branch of psychology that aims to understand how the structure and function of the brain relates to specific psychological processes
Severe epilepsy from bike accident
Neurosurgeon localized Molaison's epilepsy to his left and right medial temporal lobes (MTLs) and suggested surgical resection of the MTLs as a treatment. 
Surgery to bilaterally remove medial temporal lobes, including hippocampus
Surgery was successful in treating epilepsy
Operation 9/1953, 27 years old
Tested 4/1955, age 29
Reported date as 3/1953, age of 27
Few if any memories since operation
After the specialists left the room for a few minutes and returned, H.M. did not recognize them
IQ better than pre-op (112)
Fewer seizures
Also suffered from temporally graded retrograde amnesia
*Before his death, audio-recordings published
*Very guarded patient until he died, media never given access
Henry Gustav Molaison

23. http://thebrainobservatory. ucsd

24. H.M. Could still retrieve memories acquired long before surgery
had normal vocabulary
average IQ
intact working memory
Profound anterograde amnesia: could not form new explicit/declarative memories
General knowledge intact but “stuck in time”:
Did not learn words introduced after 1953: “Jacuzzi”, “granola”, “flower-child”
 working memory and procedural memory were intact
Molaison was able to remember information over short intervals of time
Molaison was impaired in his ability to form new semantic knowledge
He also suffered moderate retrograde amnesia, and could not remember most events in the 1–2-year period before surgery
General knowledge stuck in time:
Molaison regularly filled in crossword puzzles.[8] He was able to fill in answers to clues that referred to pre-1953 knowledge
Evidence for separate memory systems
Molaison was able to draw a quite detailed map of the topographical layout of his residence – was able to develop spatial memory

25. HM able to form some new memories: mirror trace task
However, his ability to form long-term procedural memories was intact; thus he could, for example, learn new motor skills, despite not being able to remember learning them.
improvement in H.M. for mirror tracing task (without conscious recollection of previous training episodes)
 the medial temporal lobes are not necessary for all types of long-term memory.
Milner, 1965

26. Learning a new skill: mirror-reverse reading

27. Amnesics can learn to mirror-reverse read and are sensitive to repetitions
Cohen & Squire (1980)
font is important

28. Clive Wearing Accomplished British musician Suffered from encephalitis
hippocampus destroyed in both hemispheres
frontal lobe damage as well
Retrograde as well as anterograde amnesia
memory lasts between 7-30 seconds
Wearing contractedHerpesviral encephalitis- a Herpes simplex virus that attacked his central nervous system
his memory only lasts between 7 and 30 seconds
He spends every day 'waking up' every 20 seconds, 'restarting' his consciousness once the time span of his short term memory elapses (about 30 seconds)
Read more 

29. Clive Wearing Diary entries:
8:31 AM: Now I am really, completely awake 9:06 AM: Now I am perfectly, overwhelmingly awake 9:34 AM: Now I am superlatively, actually awake
Desperate to hold on to something, to gain some purchase, Clive started to keep a journal, first on scraps of paper, then in a notebook. But his journal entries consisted, essentially, of the statements “I am awake” or “I am conscious,” entered again and again every few minutes. He would write: “2:10 P.M: This time properly awake :14 P.M: this time finally awake :35 P.M: this time completely awake,” along with negations of these statements: “At 9:40 P.M. I awoke for the first time, despite my previous claims.” This in turn was crossed out, followed by “I was fully conscious at 10:35 P.M., and awake for the first time in many, many weeks.” This in turn was cancelled out by the next entry.
Earlier entries are usually crossed out, since he forgets having made an entry within minutes and dismisses the writings–he does not know how the entries were made or by whom, although he does recognize his own writing
Read more 

30. Clive Wearing: Video (~4min.)
Wearing still recalls how to play the piano and conduct a choir – all this despite having no recollection of having received a musical education. This is because hisprocedural memory was not damaged by the virus. As soon as the music stops, however, Wearing forgets that he has just played
For full video segment see:

31. Clive Wearing Spared implicit memory
emotional memory: gradual acceptance of his condition
procedural memory: layout of his residence
From his wife Deborah:
“Clive continues to surprise us. Recently he looked at my mobile phone and asked, “Does it take pictures?”…Earlier this month I’d been with Clive, then went outside for about ten minutes. I rang the doorbell to get back in and Clive opened the door with the care assistant who had been with him the whole time. Clive said, “Welcome back!,” perfectly aware that I’d been there previously. His care assistant commented on this change. The staff also told me how one day a care assistant had lost her lighter. Ten or fifteen minutes after hearing this, Clive came up to the same lady and gave her the lost lighter, saying, “Is this your lighter?” The staff could find no explanation for his remembering who had lost the lighter or that she had lost the lighter…”
From Oliver sacks:
I spotted the two volumes of Bach’s “Forty-eight Preludes and Fugues” on top of the piano and asked Clive if he would play one of them. He said that he had never played any of them before, but then he began to play Prelude 9 in E Major and said, “I remember this one.” He remembers almost nothing unless he is actually doing it; then it may come to him. He inserted a tiny, charming improvisation at one point, and did a sort of Chico Marx ending, with a huge downward scale. With his great musicality and his playfulness, he can easily improvise, joke, play with any piece of music.
Read more 
learned new music???????
He has gained other implicit memories, too, slowly picking up new knowledge, like the layout of his residence. He can go alone now to the bathroom, the dining room, the kitchen—but if he stops and thinks en route he is lost Read more 
Molaison was able to draw a quite detailed map of the topographical layout of his residence

32. Claparède study (1911)
Claparède was a Swiss physician treating an amnesic woman
Patient never remembered having met Claparède (doctor) before
Claparède offers handshake with pinprick
Next time, no explicit memory of event
Still, patient refuses to shake hands and offers explanation: “sometimes pins are hidden in people’s hands”
Édouard Claparède, a Swiss physician who, upon shaking hands with a severely amnesic woman pricked her finger with a pin hidden in his hand. Subsequently, whenever he again attempted to shake the patient’s hand, she promptly withdrew it. When he questioned her about this behavior, she replied, “Isn’t it allowed to withdraw one’s hand?” and “Perhaps there is a pin hidden in your hand,” and finally, “Sometimes pins are hidden in hands.” Thus the patient learned the appropriate response based on previous experience, but she never seemed to attribute her behavior to the personal memory of some previously experienced event.  Read more 

33. Amnesiacs and Trivia Questions
Korsakoff patients were given feedback, then retested.
No conscious memory for items but better performance.
Their explanation: “I read about it somewhere”
The findings with trivial pursuit game show that the source memory for amnesiacs is impaired. Shimamura and Squire call this “source amnesia”.
Theory for anterograde amnesia is that binding of items to context or source might be severely impaired in amnesiacs, consistent with the idea that the hippocampus (often damaged in amnesiacs) serves the role of binding different sources of information.
Read more 
(Schacter, Tulving & Wang, 1981).

34. Can amnesics acquire any new knowledge?
Declarative memory (memory for information/knowledge, e.g. episodic & semantic memory)
 impaired
Procedural memory (e.g., how to ride a bike)
 yes
Implicit memories (using past information possibly without being aware of it)

35. Implications
Hippocampus and surrounding structures in medial temporal love are responsible for transferring explicit memories from working memory to LTM
Separate memory systems:
working memory vs. LTM
explicit vs. implicit memory

36. Memory & The Brain
Prefrontal cortex: Short term storage of explicit memories
Hippocampus: Transfers explicit memories from working memory to LTM
Cerebellum: Implicit memories of skills, habits, conditioning
Episodic or explicit memory, we know, develops relatively late in childhood and is dependent on a complex brain system involving the hippocampi and medial temporal-lobe structures, the system that is compromised in severe amnesiacs and all but obliterated in Clive. The basis of procedural or implicit memory is less easy to define, but it certainly involves larger and more primitive parts of the brain—subcortical structures like the basal ganglia and cerebellum and their many connections to each other and to the cerebral cortex. The size and variety of these systems guarantee the robustness of procedural memory and the fact that, unlike episodic memory, procedural memory can remain largely intact even in the face of extensive damage to the hippocampi and medial temporal-lobe structures. Read more 

37. To DO
Slides on repression and experiments that show that repression effects are just retrieval effects