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Memory: An Introduction
Andrea Mejia and Hana Kuwabara
Fall 2016
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Goals for Lecture

The Legacy of H.M.

Defining Memory Loss

Defining Memory
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Subtypes of Memory
Henry Molaison (i.e., H.M.)
Pre-operation
 Uncontrollable Seizures in both temporal lobes

 Removed via neurosurgery
Post-surgery (H + A +)
 Controllable seizures

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Unable to form new memories
Defining Memory: Memory Loss
Amnesia



Severe memory impairment
Usually due to injury or disease
Retrograde amnesia

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Loss of memories formed prior to an event
Accidents  disruption of memory consolidation
Anterograde amnesia


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Inability to form new memories
(i.e., H.M.)
Defining Memory
Short-term memory


Temporary information storage
Long-term Memory
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
If short-term memory is rehearsed

Enduring memory
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Extremely large (limitless?) capacity
Subtypes of LTM
LTM
Nondeclarative
(Procedural)
Declarative
Episodic
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Semantic
Skill learning
Priming
Conditioning
LTM:
Declarative vs. Nondeclarative
Declarative memory


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Memory that can be stated or described
Capital of France
Nondeclarative (procedural) memory
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Memory about perceptual / motor procedures
Demonstrated via performance (not conscious recollection)
Riding a bicycle
Declarative:
Episodic vs. Semantic
Episodic
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Detailed autobiographical memory
10th birthday party
Semantic

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Generalized declarative memory
Facts and information acquired through learning
Capital of France
Declarative memories are conscious and verbal

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Nondeclarative:
Skill learning vs. Priming vs. Conditioning
Skill learning


Learning how to perform a task by repeating the process

May include:

Sensorimotor skills (mirror tracing)

Perceptual skills (priming)
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Cognitive skills (rules and strategies)
Memories you learn by doing, not transferable by
language

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Nondeclarative:
Skill learning vs. Priming vs. Conditioning

Priming

Change in how you process a stimulus (e.g., word, picture)
because you’ve seen it (or something similar) previously

Does not require declarative memory of the stimulus
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Intact in H.M.
Nondeclarative:
Skill learning vs. Priming vs. Conditioning

Conditioning
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Involves relationships between events

Associative learning
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Classical conditioning



Instrumental conditioning (aka operant conditioning)

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Association is formed between two previously unrelated stimuli
Pavlov’s dogs
Association is formed between behavior and consequence(s)
Skinner box
Neuroanatomy of Memory
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Declarative: Formation of Memories

Medial temporal lobes (especially hippocampus)

Damage: More severe impairments when both temporal
lobes removed
Do you think hippocampus is responsible for nondeclarative
memories? What type of surgery did HM have again? What
memory complaints did he display?
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Nondeclarative: Skill learning

Different areas of the brain
Example:
 Basal ganglia, motor cortex, cerebellum – motor skills
 Cerebellum – classical conditioning
 ???? – operant conditioning

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No specific brain region identified
Because so many aspects of behavior involved?
How are memories formed?

Iconic memories
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Briefest memories (a few seconds)
From the senses  vision, hearing, smell, touch
Short-term memories
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Slightly longer than iconic memories (~ 30 seconds)
E.g., rehearsing a phone number

Subtype: Working memory


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Manipulate info for immediate use
E.g., reverse a phone number in your head
How are memories formed?
1.
Encoding
-- Raw info (sensory channels) transformed into STM
2.
Consolidation
-- STM transformed into LTM
3.
Retrieval
-- Stored info brought out of LTM for use
**Emotionally arousing experiences are remembered best
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STM vs. LTM

Hippocampal involvement

Consolidation of declarative STMs into LTMs


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Takes years (i.e. HM had retrograde amnesia for two years)
Not involved in STM “encoding” or retrieval
Effect of head trauma
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Often causes retrograde amnesia
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Without affecting older memories
May interrupt consolidation of STM to LTM
LTM: Remembering and Forgetting

No “upper limit”

Forgetting is natural
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Beneficial to forget some things

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Filter out unimportant info, free up cognitive resources
Memory interference

Proactive interference  Previously learned info interferes
with learning of new info

Retroactive interference  Newly learned info interferes with
previously learned info
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Memory:
Cellular Mechanisms of Memory
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Defining learning and memory

Learning



Change in behavior due to experience (permanent?)
Learning vs. memory

Learning = information acquisition

Memory = storage and retrieval
What does learning include?
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Simple learning and neural changes

Classical (Pavlovian) conditioning


Previously neutral stimulus + A response normally generated by
another previously learned cue
Operant Conditioning

Type of learning in which strength of a behavior is modified by the
behavior’s consequences

Reinforcement (increase the behavior)


Punishment (decrease the behavior)

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Positive and negative (adding something and taking something away)
Positive and negative (adding something and taking something away)
Habituation


Stimulus is presented repeatedly / often

Organism stops responding to it

Begins within hours of human life
Survival value

Ignore stimuli that do not cause irritation or harm

Free to attend to other stimuli
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Sensitization

Opposite of habituation

Animal learns to respond vigorously to a previously
neutral stimulus

Survival value

Presence of a noxious or irritating stimulus

Animal learns to regard it as dangerous, avoid it
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Classical Conditioning (associative learning)
Unconditioned stimulus (US)
Dog food
Neutral stimulus
Bell ringing
Unconditioned stimulus (US)
Dog food
Conditioned stimulus (CS)
Bell ringing

Unconditioned response (UR)
Salivation
Unconditioned response (UR)
Salivation
Conditioned response (CR)
Salivation
Cerebellum may be more involved than hippocampus
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