Download Memory - UCSD Cognitive Science

COGNITIVE
SCIENCE
17
Can You
Remember
My Name?
Part 1
Jaime A. Pineda, Ph.D.
The Persistence of Memory
Dali, 1931
Nature of Learning
(synaptic plasticity)
• Experiences produce changes in the brain (learning)
– Perceptual: the ability to identify and categorize objects through
our senses (knowing about things); takes place in sensory systems
– Motor: the ability to identify and categorize things through our
motor systems (knowing what to do)
– Stimulus-response: establishing an association between a
stimulus perception and a motor response
• Classical and instrumental conditioning (Hebbian rules/LTP and LTD)
– Relational: the relationships among individual stimuli
• Spatial
• Episodic
• Observational
Nature of Memory
– Changes in the brain as a result of
experiences are retained for a period of
time (memories)
– How and where are memories stored?
• Karl Lashley – “memory is not possible”
• Memories are highly distributed
Memory
The ability to retain learned information and
knowledge of past events and experiences
and to be able to retrieve that information.
Learn ---- Retain ---- Retrieve
Encoding ---- Maintenance ---- Retrieval
Organization of experience….what would you
do without it?
Brain Research In the Media…
Common Model of Memory
Processes
Rehearsal
Sight
Elaboration
and
Organization
Smell
Sound
Sensory
Memory
Attention
Short-Term
Memory
Long-Term
Memory
Retriev al
Taste
Touch
Lost
Lost
Time Course of Memory Processes
Memory Processes
Sensory
Short Term
Long Term
Holds information
for a fraction of a
second
Information remains Information remains
for about 15-20
for days, months,
seconds
and years
Perception and
attention
Chunking
Retrieval:
Rehearsal: Rote and More frequent
Elaborative
activation of neuron
patterns leads to
more efficiency
Memory Dichotomies
•
•
•
•
working (short-term) vs. long-term
episodic vs. generic
explicit vs. implicit
procedural (riding a bike) vs. declarative
Types of Memory
Working memory:
An active system for temporarily storing and
manipulating information needed in the
execution of complex cognitive tasks (e.g.,
learning, reasoning, and comprehension)
(Baddeley 1986)
– The “magic number” (+ 7) for digit span, and more.
– Sets a limit on performance, good thing?
– “Loading platform” for long term memory
149162536496481
Memory Processes
• How do memories get from working
memory to long term memory storage?
– consolidation
• How do we get them back?
– Retrieval
– Indexing
What Facilitates Encoding,
Consolidation, and Maintenance?
• Time spent in working memory?
rehearsal?
• Attention and engagement
• Connection to what we already know
• Depth of processing (typeface vs.
meaning)
What Facilitates Retrieval?
• Memory cues & context
• Depth of processing, easier to find
• Retrieval failure or memory loss? Or
forgetting vs. misplacement?
Forgetting
We are forgetting all the time.
Decay-- metabolic processes undo
“memory traces”
Displacement-- awake vs. asleep during
recall interval, interference
1 4 9 16 25 36 49 64 81
ta-da!
Long Term Memory
Squire’s Taxonomy of Memory
Squire & Zola, PNAS, 1996
Memory Disorders
Two main types of Amnesia:
• Anterograde (“forward”) Amnesia
• Retrograde (“backwards”) Amnesia
Memory Disorders
Anterograde Amnesia
• Problem: forming new memories postinjury/operation
• Korsikoff’s Syndrome (chronic alcoholics),
Alzheimer’s, patients like H.M. with
hippocampal/thalamus damage
• Can read, write, converse, remember life until
damage was done
H.M.:
• “Right now, I’m wondering, Have I done or said
anything amiss? You see, at this moment
everything looks clear to me, but what happened
just before? That’s what worries me. It’s like
waking from a dream; I just don’t remember.”
• “…Every day is alone in itself, whatever
enjoyment I’ve had, and whatever sorrow I’ve
had.”
Memory Disorders
Retrograde Amnesia:
• Problem: loss of memory for some period before
brain injury
• ECT and head traumas
• “Trace consolidation theory” -- memory hasn’t had
time to become firmly established, but... several
years?
• Sometimes memories do come back gradually
Memory Disorders
What amnesiacs can do:
• procedural memory tasks (mirror
tracing)
• implicit memory tasks
• behavioral conditioning
Squire’s Taxonomy of Memory
Squire & Zola, PNAS, 1996
Memory in the Brain
Other important brain areas and functions:
• Pre-frontal cortex—retrieval, working memory
• Hippocampus & other parts of Thalamus-consolidation
• Amygdala--emotional events, fear
conditioning
• Occipital & Temporal Lobes—
visual/auditory memories