Download Long-Term Memory (LTM) Outline Explicit

2/13/2017
Outline
• Types of long-term memory
Long-Term Memory (LTM)
– Implicit / Explicit
• How do we store?
• What do we store?
• How durable is the store?
Explicit Memory
Semantic memory –
not tied to specific
time or place
Implicit Memory
Episodic memory –
tied to specific events
My first ride on
a roller-coaster!
Date of signing of
US Constitution
My best friend’s
middle name
My worst break-up
Capitol of New
York?
• Often a procedure
• Does not require conscious recognition
• Conscious thought may interfere
• Can measure changes in
reaction / performance
My favorite birthday
party
Outline
How are memories stored?
• Types of long-term memory
• Physical Location?
• Synapse Strength?
– Implicit / Explicit
• How do we store?
• What do we store?
• How durable is the store?
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How are memories stored?
• Physical Location?
• Instead, errors
in learning
increased
with amount
of cortex
lesioned
• Lashley (1950)
– Trained rats on various tasks
– Then lesioned rat cortices in an attempt to find
out where those behavioral memories were
stored
– Couldn’t find them in a single place
How are memories stored?
(Definitions for Prev. slide*)
• Physical Location?
• Engram – The package of information that
makes up a memory
– the bound representation of experienced
events, including: perceptual and conceptual fragments,
• Lashley (1950)
– “It is not possible to demonstrate the isolated
localization of a memory trace anywhere within
the nervous system. Limited regions may be
essential for learning or retention of a particular
activity, but within such regions the parts are
functionally equivalent. The engram is
represented throughout the region.”
self-generated thoughts, contextual details, etc…
• Trace – a pointer to the memory for retrieval
(*Will not test on these)
How are memories stored?
How are memories stored?
• Physical Location?
• Physical Location?
• Synapse Strength?
• Lashley (1950)
– “every instance of recall requires the activity of
literally millions of neurons. The same neurons
which retain the memory traces of one experience
must also participate in countless other activities.”
• Recall Hebbian Learning?
– Cells that fire together
wire together
• Changing synaptic
potential stores
information
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Hebb 1949
Classical Conditioning
• Classic work of
cognitive neuroscience
• Lays out Hebb’s
hypotheses on
learning
Whtvr…
Response is physiological and subconscious
Physiology of Mind (Structuralism)
Hebb 1949
• Wilhelm Wundt
(1832-1920)
• Each neuron has tons
of connections
• Cells fire in networks
• Some cells will be
linked in groups
• These “assemblies” may “reverberate”
• Sensation does not
differ from ideation
• “Blue is and remains
blue”
(whether sensed or
imagined)
Image and dates: https://en.wikipedia.org/wiki/Wilhelm_Wundt
Hebb 1949
• Even simple
assemblies might
reverberate for…
half a second?
• Reverb = short term
memory?
• Leads to continued
firing / wiring =
learning?
Hebb 1949
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However, in vivo…
However, in vivo…
• We can try and record out of
cells during a task
• Do we see lasting reverb?
• Record out of MT in
awake monkey
• Monkey sees motion
sample
• Delay
• Monkey responds
“same/different” to
test stimulus
Tania Pasternak, PhD
University of Rochester
Professor, Neurobiology
& Anatomy, Brain &
Cognitive Sciences,
Center for Visual Science
Bisley, J.W., Zaksas, D., Droll, J.A., & Pasternak, T. (2004). Activity of Neurons in Cortical Area MT During a Memory for Motion Task.
Journal of Neurophysiology. Jan 2004, 91 (1) 286-300; DOI:10.1152/jn.00870.2003
However, in vivo…
• Activity drops
off almost
immediately
• Poor evidence
of local reverb
Bisley, J.W., Zaksas, D., Droll, J.A., & Pasternak, T. (2004). Activity of Neurons in Cortical Area MT During a Memory for Motion Task.
Journal of Neurophysiology. Jan 2004, 91 (1) 286-300; DOI:10.1152/jn.00870.2003
Bisley, J.W., Zaksas, D., Droll, J.A., & Pasternak, T. (2004). Activity of Neurons in Cortical Area MT During a Memory for Motion Task.
Journal of Neurophysiology. Jan 2004, 91 (1) 286-300; DOI:10.1152/jn.00870.2003
Frontal Areas?
• Perhaps activity is maintained in other areas?
• Working memory suggests frontal areas…
Curtis, C. E., Rao, V. Y., & D'Esposito, M. (2004). Maintenance of spatial and motor codes during oculomotor delayed response tasks. Journal of
Neuroscience, 24(16), 3944-3952.
Brain activation?
Frontal Areas?
• Curtis & D’Esposito (2003)
• Dorsolateral Prefrontal
Cortex (DLPFC)
• Propose 4 major areas
for working memory:
• Perhaps activity is maintained in other areas?
• Working memory suggests frontal areas…
• Similar human fMRI task
– (P) Parietal areas
• Stores information for
location of objects
– (F) Frontal Eye-Fields
• Visuospatial buffer
– Stim
– Delay
– Respond (match / non-match)
– (B) Broca’s Area
• Phonological buffer
– (D) DLPFC
• Central Executive
Curtis, C. E., Rao, V. Y., & D'Esposito, M. (2004). Maintenance of spatial and motor codes during oculomotor delayed response tasks. Journal of
Neuroscience, 24(16), 3944-3952.
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Yes! But…
Complex interplay of areas?
• There appears to be a role of frontal cortex in
maintaining information
• But that’s more like working memory
• Remember –
– Lashley: Memory is distributed
– Lots of small changes add up?
• How do the circuits change at the lower
levels?
Distributed Neural Networks
Distributed Neural Networks
• How could memory be so distributed?
• Formed of multiple layers of “nodes” /
neurons
• Nodes/neurons in one level pass info onto
nodes/neurons in the next level
• Patterns of activation in level thus can cause a
specific pattern of activation in the next group
of nodes/neurons
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Distributed Neural Networks
Distributed Neural Networks
• Through learning and feedback,
weights between nodes/neurons can change
• This changes the information represented in
the network
• Example: handwritten letter detection
• Online demos:
http://www.mitchcrowe.com/visualizingneural-networks/
Distributed
•
Example
with Visual
Neural
Retinal Networks
Areas
Ganglion
Rods &
Cells
Example:
handwritten
Cones
Inferior
letter detection
Temporal
Areas
Input
V1, V2,
etc…
Distributed Neural Networks
This IS Artificial
Intelligence!
• Example: handwritten letter detection
Conscious
Recognition
Clinical Cases…
• Are there parts of the brain that knock out
storage to LTM?
Clive Wearing
BBC – Man Without a Memory
Clip: https://www.youtube.com/watch?v=Vwigmktix2Y
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Also, H.M. (Henry Molaison)
• 1953, Doctors try experimental surgery to
relieve seizures
• Remove parts of Hippocampus & Temporal
lobe (function then unknown)
• Post surgery, H.M. could no longer form new
memories
E.P.
PBS - American Scientific Frontiers (2004)
https://www.youtube.com/watch?v=7Grh3PeEMIg 3:10 – 11:16
H.M.’s brain online
All suffered damage to Hippocampus
• http://hm.brainandsociety.org/hm
_web/
• Hippocampus is part of the limbic system
• Located in the medial temporal lobe
• Essential to moving information from
WM to LTM
Lesion
Cellularlevel
resolution
Role of Hippocampus?
• How does hippocampus get info from WM to
LTM?
• Unclear.
• But, consider:
– Hippocampus reactivates recent experiences
during “off-line” periods (rest & sleep)
(Sutherland & MacNaughton, 2000; Davidson, et al, 2009)
(Will discuss more in consciousness lecture)
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Role of Hippocampus?
HM –
Mirror Drawing
• Also note: These were formation of explicit
memories
• What about implicit memories?
Role of Hippocampus?
• Also note: These were formation of explicit
memories
• What about implicit memories?
– At first blush, would appear that this relies on
other areas…
– This was the consensus for years
– But…
Recent re-evaluation of H.M.’s brain
• 2014 -- 3D reconstruction
• Shows that a sizable portion of the
hippocampus remained intact
(shown in green on next slide)
Annese, J., Schenker-Ahmed, N. M., Bartsch, H., Maechler, P., Sheh, C., Thomas, N., ... & Klaming, R. (2014). Postmortem examination of
patient HM’s brain based on histological sectioning and digital 3D reconstruction. Nature communications, 5.
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Role of Hippocampus
• E.P. had more complete hippocampal damage
• E.P. was NOT able to form new implicit
memories
• Hippocampus appears important for all types
of memory encoding
– (Implicit memory tasks may just require fewer
resources)
Outline
• Types of long-term memory
– Implicit / Explicit
• How do we store?
• What do we store?
• How durable is the store?
Priming & Depth of Encoding
Priming & Depth of Encoding
• Depth of Encoding – the more you interact
with and manipulate data, the more you
remember it
• Jacoby & Dallas (1981)
• Stage 2: participants were divided into two
groups. Each received one task:
• Jacoby & Dallas (1981)
– Recognition
• Stage 1: Three types of questions followed by word
– Perception
– Q1: Constituent letters of words (Physical features)
• Does the word have the letter L?
– Q2: Rhyme question (Phonemic features)
• Does the word rhyme with book?
– Q3: Meaning question (Semantic features)
• Is the word an animal?
(Did this word appear in stage 1?)
(Try to read a word that is flashed briefly on the screen)
What kind
of Memory
are these?
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Jacoby and Dallas (1981)
• Recognition memory
increased with
Level of Processing
• For the perceptual group,
words that appeared in
stage 1 were read faster,
no level of processing
trend.
• (Perceptual memory
fairly independent of
recall.)
How do we get things out of memory?
• When we learn, we make connections
between the material we’re learning, and
what we already know
• These connections can serve as retrieval
paths
Example: Retrieval Cues
Neural Networks, Levels of Processing
• Q: Why does attention to meaning (e.g., deep
processing) lead to better recall?
• A: When the meaning of an item is attended
to, many more memory links are provided to
that item so retrieval is easier.
Memory as Associative Network
• Like a Neural Network at the Concept /
Category level
– A “node” for each piece of information
– links between nodes that are “associated”
– when one node is activated, it spreads activation
to all nodes it’s linked to
– if an node receives input from multiple nodes, it
will be “more active” = easier to reach threshold
for remembering
Memory as Associative Network
What is the capital of South Dakota?
hint: it’s also a man’s name!
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Memory as Associative Network
• context-dependent
learning
– Godden & Baddeley
(1975)
Context-Dependent Learning
Divers under water and divers on land
learned a list of 36 words aurally then
½ of them switched environments, and
wrote down as many words from the lists
as possible in 2 min.
Context-Dependent Learning
Context-Dependent Learning
• Context-reinstatement: improved memory
performance when tested in the same
context that was in place during learning
– Context influences how you think about the
information
Recall from Spreading Activation
State-Dependent Learning
• Activating one concept
leads to activation
of related concepts
• # of connections:
more access points
• Emotion can also provide a learning context:
Think of arrows
as two-way
access paths
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Outline
• Types of long-term memory
– Implicit / Explicit
• How do we store?
• What do we store?
• How durable is the store?
Familiarity
Familiarity
• Without looking at one,
• Try to draw a US penny from memory
• Examples of what people draw
Baddeley (1999), based on Rubin, D. C., & Kontis, T. C. (1983). A schema for common cents. Memory & Cognition, 11(4), 335-341.
Familiarity
False Memories
Actual Coins from that year
Participant Average (Mode)
Rubin, D. C., & Kontis, T. C. (1983). A schema for common cents. Memory & Cognition, 11(4), 335-341.
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Illusion of Truth
Illusion of Truth…
• Hasher, Goldstein, & Toppino (1977)
– Participants rate repeated statements
as more true than new statements
• Bacon (1979)
– Even hearing parts of a statement
(e.g. The Statue of Liberty)
lead people to rate related statements
as more true
(“The statue of Liberty’s arm is 46 ft long.”)
Begg, I. M., Anas, A., & Farinacci, S. (1992). Dissociation of processes in belief: Source recollection, statement familiarity, and the illusion of truth.
Journal of Experimental Psychology: General, 121(4), 446.
2009
2017
Illusion of Truth…
• “This was the largest audience ever to witness
an inauguration, period”
http://time.com/4641381/donald-trump-inauguration-crowd/?xid=homepage
https://www.nytimes.com/interactive/2017/01/20/us/politics/trump-inauguration-crowd.html?_r=0
http://stmedia.startribune.com/images/211Trump_Inauguration.jpg
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Non-famous  Famous Faces
Illusion of Truth…
• Landau & Leed
(2012)
• Nonfamous
faces paired with
“famous” or
“semifamous”
faces
• Task: Rate
“Would these
two people
make strong
business
partners?”
Landau, J. D., & Leed, S. A. (2012). The illusion of fame: How the nonfamous become famous. The American journal of psychology, 125(3), 351-360.
Non-famous  Famous Faces
• Later, asked to
rate individual
faces on how
famous
• Newly familiar
faces rated as
more famous
John C. Lilly
“Reality is a
matter of local
custom”
(1915-2001)
Developed Flotation Isolation Tanks
Gave LSD to dolphins & self to try and
communicate
Landau, J. D., & Leed, S. A. (2012). The illusion of fame: How the nonfamous become famous. The American journal of psychology, 125(3), 351-360.
Photo: Thinking Allowed (1983). PBS / Thinking Allowed Productions; Quote: Lilly, JC & Gold, EJ (1996) Tanks for the Memories: Flotation Tank Talks. Gateway
Constructionist Approaches of LTM
Alas, the film eventually
was lost, wrote Gertie,
“and we all began to
remember the night
differently—each
memory perfectly true
and exactly how it
happened, of course.”
• Memory is not a file-drawer
• Not for remembering past events
Gertrude Sanford
• Useful for prediction
• We create reasonable accounts from limited
data
(1902-2000)
- Dickey, Christopher (2016)
https://goo.gl/PgOqWJ
American Socialite /
WWII Spy
Painting: William Orpen, 1922
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Constructionist Approaches of LTM
Greenberg (2004)
• Isolated details remembered:
– reasonable story created during recall to
rationalize the details
• General theme (only) remembered:
Pearl Harbor, December 7, 1941
– detail often added to give credibility and
coherence to the story
• **This all happens subconsciously and we
believe the recall as if it were reality.
“I was listening to a baseball game on the
radio when it was interrupted by an
announcement of the Pearl Harbor attack.”
1941 Baseball schedule: April through September
Fall 1988 two years after the incident, student “RT”
Fair Trial…
• If source & details are fragile…
– Can we change recollection through leading
questions?
24 hrs after the explosion, student “RT”
Neisser & Harsch, 1992
• Participants shown films
of traffic accidents
• Then asked questions with varied verbs:
• “About how fast were the cars going when
they _____ each other?”
– Contacted
– Hit
– Bumped
– Collided
– Smashed
Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of automobile destruction […] . Journal of verbal learning and verbal behavior, 13(5), 585-589.
Loftus & Palmer (1974)
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MEAN SPEED ESTIMATE (MPH)
Loftus & Palmer (1974)
40
35
30
25
VERB
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Wade, Garry, Read, & Lindsay (2002)
“A picture is worth a thousand lies”
Loftus (1975)
• Personal Experiences can be altered, too:
• Study about “headaches” (N=40)
– In terms of the total number of products,
how many other products have you tried? 1? 2? 3?
– In terms of the total number of products,
how many other products have you tried? 1? 5? 10?
– Do you get headaches frequently, and, if so, how often?
– Do you get headaches occasionally, and, if so, how often?
Avg 3.3
Avg 5.2
• “Twenty adult confederates each recruited a family
member who (1) had not taken a hot air balloon ride,
(2) was at least 18 years old, and (3) had not taken a
psychology class”
• “The confederates each provided a selection of
photographs in which the subject was 4–8 years old”
Avg 2.2/wk
Avg 0.7/wk
Loftus, E. F. (1975). Leading questions and the eyewitness report. Cognitive psychology, 7(4), 560-572.
Wade, Garry, Read, & Lindsay (2002)
“A picture is worth a thousand lies”
Wade, K. A., Garry, M., Read, J. D., & Lindsay, D. S. (2002). A picture is worth a thousand lies: Using false photographs to create false childhood
memories. Psychonomic Bulletin & Review, 9(3), 597-603.
Wade, Garry, Read, & Lindsay (2002)
“A picture is worth a thousand lies”
• 50% of participants recalled the balloon ride
with lots of additional details
Hopeless?
• Overall, memory is pretty good
– We can remember soooo much stuff!
• But, memory is also highly malleable
• Highly prone to suggestion
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