Transcript ppt

Cognitive Neuroscience (Psychology 460)
Summer Quarter
Mondays & Wednesdays 12:00 – 2:10pm
This course will focus on answering the question,
“How are cognitive behaviors produced by the human brain?”
Topics include language, attention, action, cognitive control, and
memory. The course will involve lectures, discussions, demonstrations,
and tours of some of the neuroscientific tools we have on the UW
campus.
Retrieval, Memory Modification
and The Cycle of Consolidation
Psychology 355: Cognitive Psychology
Instructor: John Miyamoto
05/09/2016: Lecture 07-1
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Outline
• Brunet’s treatment of unwanted memories in PTSD patients.
• The cycle of consolidation
Lecture probably
ends here
• Introduction to autobiographical memory
Psych 355, Miyamoto, Spr ‘16
OLD SLIDE: Nader’s Method for Undoing Fear Conditioning
3
Undoing Fear Conditioning in the Rat
Skim past:
Nader, K., Schafe, G. E., & Le Doux, J. E. (2000). Fear memories require protein synthesis in the
amygdala for reconsolidation after retrieval. Nature, 406, 722-726.
• If a tone is paired with an electric shock, a rat will learn
to freeze when it hears the tone (classical conditioning of fear).
• Anisomycin – antibiotic that inhibits protein synthesis that
is required in the formation of new memories.
• Administering anisomycin to a rat can cause it to fail to learn.
Psych 355, Miyamoto, Spr '16
Experimental Design (Diagram of Rat Learning or Unlearning)
4
Summary of Main Finding
Skim past:
Condition 1:
Day 1: Tone + Shock + anisomycin
Day 2: No drug; no tone; no shock
Day 3: Does not freeze to tone
Combining drug with tone &
shock on Day 1 prevents
fear conditioning.
(shows no learning)
Condition 2:
Day 1: Tone + Shock
Day 2: Drug; no tone; no shock
Day 3: Freezes to tone
Drug on Day 2 does not undo
fear conditioning.
(shows learning)
Condition 3:
Day 1: Tone + Shock
Day 2: Drug + tone, no shock.
Day 3: Does not freeze to tone
(shows no learning)
Psych 355, Miyamoto, Spr '16
Combining drug with retrieval
of fear conditioning on Day 2
undoes fear conditioning.
Retrieval Makes Day 1 Learning Vulnerable to Change
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Interpretation
• Retrieval makes the fear conditioning from Day 1 vulnerable to change.
Combining retrieval with drug prevents reconsolidation of memory of fear
conditioning, thereby causing loss of conditioning.
Condition 3
displayed
to the right:
Day 1
Day 2
Day 3
• Nader et al. (2000) state that the memory trace is "labile" during retrieval,
i.e., its form can be changed at that time.
Psych 355, Miyamoto, Spr '16
Using Fragility of Memories During Retrieval to Treat PTSD
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Using the Fragility of Memories During Retrieval to Treat PTSD
Brunet, A., Orr, S. P., Tremblay, J., Robertson, K., Nader, K., & Pitman, R. K. (2008). Effect of postretrieval propranolol on psychophysiologic responding during subsequent script-driven traumatic
imagery in post-traumatic stress disorder. Journal of Psychiatric Research, 42, 503-506.
Skim past:
• Post-traumatic stress disorder (PTSD): Strong fear and stress
responses are evoked by reminders of the initial traumatic event.
• Brunet et al. asked whether human PTSD patients can lose
or at least diminish their fear and stress conditioning by
techniques that are similar to Nader et al.'s demonstration
that rats can lose their fear conditioning.
♦
Study used propranolol, a drug that is used to prevent traumatic memories
if administered immediately following a traumatic event. Propranolol
reduces the fear & stress conditioning of trauma.
Psych 355, Miyamoto, Spr '16
Brunet et al.'s Subjects Were PTSD Patients
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Brunet et al.'s Study of PTSD Subjects
Skim past:
• PTSD patients: Childhood sexual abuse, motor vehicle accident, rape,
being taken hostage.
♦
Comorbid mental disorders included: major depressive disorder, panic
disorder, social phobia, bulimia, generalized anxiety disorder.
• Two scripts were prepared for each patient that described the
events that produced the trauma for that patient.
• 19 PTSD patients were randomly assigned to either
a TREATMENT Condition or a CONTROL Condition.
(Conditions described on next slide.)
Psych 355, Miyamoto, Spr '16
Test of Treatment - Was It Efficacious?
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Brunet et al.'s Study: Treatment and Control Conditions
Patient hears recorded description
of traumatic experience
Patient is injected
with propranolol.
7 Days
Patient is injected
with placebo.
7 Days
Patient hears
another recorded description
of traumatic experience
Patient hears
another recorded description
of traumatic experience
Measure anxiety
Measure anxiety
Psych 355, Miyamoto, Spr '16
Test of Treatment - Was It Efficacious?
9
Test of Treatment
Skim past:
• One week later, the patients listened to a taped version of
the scripts that described their traumatic experience, and
are asked to imagine the traumatic events while listening to the tape.
♦
Physiological measures of stress and anxiety are taken while patients
listen to the tape.
• Question: When the patients hear the taped version of traumatic
experience, will they experience fear, anxiety, etc. of PTSD?
♦
I.e., has the drug treatment reduced or eliminated their tendency to
associate fear responses with these memories.
Psych 355, Miyamoto, Spr '16
Analogy Between Rat Conditioning and PTSD Treatment
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Analogy Between PTSD Treatment & Conditioning
HUMAN
Traumatic experience
Listen to taped
description of
traumatic experience
Injection of propranolol
immediately after recall
RAT
Tone + shock conditioning in the rat
Rat hears tone without the shock
Injection of anisomycin
immediately after rat hears tone
?
Later, will the human seem to
have unlearned the fear
conditioning to the traumatic
memories?
Psych 355, Miyamoto, Spr '16
Later, the rat seems to have
unlearned the fear conditioning
to the tone.
Experimental Results
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Tensing of
Frowning Muscles
Y-Axis Are Z-Scores Relative to Base Rate
Brunet et al. Results
Heart Rate
Skin Conductance
Corrugator EMG
• Grey = placebo group; Black = propranolol group
• Result: Therapy reduces original fear conditioning.
Psych 355, Miyamoto, Spr '16
Return to Malleability of Memory During Retrieval
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Tensing of
Frowning Muscles
Y-Axis Are Z-Scores Relative to Base Rate
Brunet et al. Results
Heart Rate
Skin Conductance
Corrugator EMG
• Grey = placebo group; Black = propranolol group
• Result: Therapy reduces original fear conditioning.
Psych 355, Miyamoto, Spr '16
Return to Malleability of Memory During Retrieval
13
Malleability of Memories During Retrieval
• Learned associations can be lost during retrieval
♦
Rats unlearned tone-shock connection
♦
Humans unlearn (to some degree) the association between a
traumatic episodic memory and the emotional response.
Psych 355, Miyamoto, Spr '16
This Slide + Retrieval Strengthens Memory (Consolidation/Reconsolidation)
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Malleability of Memories During Retrieval
• Learned associations can be lost during retrieval
• Consolidation & Reconsolidation –
Memories can be strengthened during retrieval.
♦
Thinking about something produces better future recall.
♦
Practice testing (retrieval) produces better future recall.
♦
The memory becomes more primed,
i.e., more easily retrieved as an associate of something else.
Psych 355, Miyamoto, Spr '16
This Slide + Query: Do These Facts Contradict Each Other?
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Malleability of Memories During Retrieval
• Learned associations can be lost during retrieval
• Consolidation & Reconsolidation –
Memories can be strengthened during retrieval.
• Do these results contradict each other?
No!
• Stored representations can change during retrieval.
♦
Usually the change makes the memory stronger, better organized,
more linked to other memories. The memory becomes more primed,
i.e., more easily retrieved as an associate of something else.
♦
The opposite can also happen,
○
○
E.g., rats unlearn their fear conditioning, or humans become desensitized to memories
of trauma. This is a special case that is based on the injection of drugs that would not normally be present.
E.g., while we think about past events, i.e., during retrieval, we may distort the facts or
even falsify what was once a true memory. Psychologists believe that this happens to everyone.
Psych 355, Miyamoto, Spr '16
Conclusions re Consolidation
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Conclusion re Consolidation
• Consolidation occurs through reactivation of memories,
followed by re-encoding of the memories.
• Hippocampus plays a major role in reactivation of recent episodic
memories.
♦
Standard Model of Consolidation:
After the memories have been consolidated,
the hippocampus plays a reduced role in retrieval of episodic memories.
♦
Multiple Trace Model of Consolidation:
After the memories have been consolidated, the
hippocampus plays a reduced role in retrieval of episodic memories that have been semanticized
(turned into semantic memories, i.e., “remember” the memory), but not for episodic memories that
continue to be episodic, i.e., “know” that this is what happened.
• Memories are malleable during or shortly after retrieval.
• PBS video titled “Memory Hackers”:
https://www.youtube.com/watch?v=xS_OiKvoqbo
Excellent discussion of how memories are created.
Thank you, Lindsay.
Psych 355, Miyamoto, Spr '16
The Cycle of Consolidation
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The Cycle of Consolidation
Cycle of consolidation (JM’s term):
♦
Repeatedly retrieving some memories.
♦
Possibly modifying the memories.
♦
Reconsolidating the memories, possibly with modifications.
• The cycle of consolidation happens spontaneously in many different
situations.
Psych 355,, Miyamoto, Spr '16
Image of a Man Thinking About a Conflict with Significant Other
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Not-So-Instant Replay of Interpersonal Conflict
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Psych 355, Miyamoto, Spr '16
Image of a Man Thinking About How to Compute a T-Test
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Statistics Problem Solving
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Psych 355, Miyamoto, Spr '16
Dwelling On Something Involves Lots of Retrievals – END
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Dwelling on Something Usually Involves Lots of Retrieval
• Retrieval creates a the potential for modification of memories.
• Retrieval induced memory change happens very often.
• We spontaneously engage in thinking patterns that cause
retrieval-induced memory change. This is the cycle of consolidation.
♦
Retrieval induced memory change is not just a tool for better study habits.
♦
Retrieval induced memory change is not just a tool for clinical modification
of memories.
Psych 355, Miyamoto, Spr '16
END – OR – Start Autobiographical Memory
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Autobiographical Memory (AM)
• Autobiographical memories are memories of one's personal
experiences and history.
• Many autobiographical memories include episodic memories.
♦
E.g., I remember listening to a lecture on statistical theory last week,
i.e., I remember where I was sitting in the room, who was around me, etc.
• Many autobiographical memories include semantic memories.
♦
E.g., I remember the name of my elementary school, but the name
isn’t connected to a particular experience.
Psych 355, Miyamoto, Spr '16
AM & Mental Imagery
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AM & Mental Imagery
• AM’s often include memories of visual, auditory, olfactory or
haptic aspects of the memory.
♦
Memory of a place might include a visual memory.
♦
Memory of food might include visual or olfactory aspects.
• Greenberg and Rubin (2003)
♦
Patients who cannot recognize objects also experience loss
of autobiographical memory
♦
Visual experience plays a role in forming and retrieving AM
Psych 355, Miyamoto, Spr '16
Do AM’s Involve Distinct Patterns of Brain Activity?
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Do AM’s Involve Distinct Patterns of Brain Activity?
• Subjects (Duke undergrads) took
photos of campus landmarks.
• Later subjects viewed photos during
fMRI scan.
OWN Photos: Photos taken by the
subject.
LAB Photos: Photos taken by someone
else, not by the subject.
Figure 8.1
Goldstein, p. 209, based on Cabeza, Prince,
Daselaar, Greenberg, Budde, Dalcos, et. al.
(2004).
Psych 355, Miyamoto, Spr '16
fMRI Results for OWN and LAB Photos (text description)
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fMRI Results for OWN Photos & LAB Photos
• Both types of photos activated similar brain structures
♦
Medial temporal lobe (MTL) (typical of episodic memory)
♦
Parietal cortex (typical of scene processing)
• OWN-photos activated more of the
♦
Prefrontal cortex (PFC) (information about self)
♦
Hippocampus (recollection)
Psych 355, Miyamoto, Spr '16
These interpretations
involve theory
(intelligent guesswork).
fMRI Results for OWN and LAB Photos (fMRI Images)
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fMRI Images that Support Interpretation on Preceding Slide
(a) Parietal cortex
(c) Hippocampus
Figure 8.2. fMRI response in three brain
regions.
• Yellow lines: Response to OWN
photos
• Blue lines: Response to LAB photos
(b) Prefrontal cortex (PFC)
Psych 355, Miyamoto, Spr '16
• OWN photos produce stronger
response than LAB photos in
PFC & hippocampus.
END
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