Pcb - Memory Lecture 3 From Slides

Front 1

What is Fp1 & Fp2?

Back 1

Fp1 = Lateral Frontopolar area (BA10) 1

Fp2 = Medial Frontopolar area (BA10) 2

2 cytoarchitectonically & functionally distinct areas of of frontopolar cortex

Front 2

What are Fp1 & Fp2 involved in?

Back 2

Fp1 = Cognition, working memory & perception

Fp2 = Affective/emotional processing & social cognition

Front 3

What happens during retrieval of memories?

Back 3

Prefrontal cortex involved in filtering of information from useful brain areas for a goal e.g.:

- Location from Parietal lobe

- Colour from Temporo-occipital area

- Shapes from Inferotemporal area

Front 4

What was the task used by Anderson et al., to study inhibition/repression of memories?

Back 4

Think/No-think paradigm

1. Participants trained with list of unrelated word pairs (e.g. Ordeal-Roach)

2. When they see 'Ordeal' will therefore respond with 'Roach' when tested

3. Then asked to either think about the associated word or suppress it from memory during presentation of the first-word for ~4s (scanning period)

4. More they try to not think about a word, the less likely they were to retrieve it on test

5. Error even occured when they were given an "independent probe" test where the cue was a category e.g. Insect-____

Front 5

What did Anderson & Green the results of their Think/No-think test support?

Back 5

Support existence of inhibitory control mechanism that gives people ability to suppress unwanted memories.

- Unlikely to be due to un-learning of association or interference from competing associates to the trained cue

Front 6

What else did Anderson et al., study?

Back 6

fMRI response to memory suppression

Areas active more during suppression than respond conditions:

- Bilateral dorsolateral & ventrolateral PFC (DLPFC & VLPFC)

- Anterior cingulate cortex (ACC)

- Pre-supplementary motor area

- Intraparietal sulcus

Suppression reduced activity in the hippocampus

Front 7

Who else studied memory inhibition and how did they do this?

Back 7

Wimber et al., 2015

1. Participants trained on novel word-picture pairs, each word being linked with 2 associates.

2. During scanning, participants were cued with a word and asked to retrieve the first associate that they studied (target) e.g. Marylin Monroe face

- The second associate (competitor e.g. Hat) was assumed to interfere with retrieval of the first

3. On each trial, subjects classified memory that came to mind with either face, object, scene or unsuccessful retrieval

Front 8

What were the results of Wimber et al., 2015 study on memory inhibition?

Back 8

1. When chose wrong category, much more likely to choose category of competitor than a scene/unknown category they hadn't been shown

2. Linear decrease in interference of competitor stimuli during selective retrieval across trials.

3. Ventral visual cortex & hippocampus showed evidence of target-unique memory reinstatement.

3rd trial = Highest activity in ventral visual cortex

4th trial = Highest activity in hippocampus but NOT ventral visual cortex

Suggests that unique memory was reinstated increasingly over repetitions

4. Competitor activation in ventral visual pathway declined significantly across repeated trials

5. Ventrolateral PFC (VLPFC) is source of top-down inhibitory modulation that suppresses cortical patterns of competing memories

Front 9

Who studied false memories in 2002 and how?

Back 9

Wade et al., 2002

Used doctored photographs or fake narrative to create false child-hood memories in adults of a hot-air balloon ride

Subjects tried to remember false event & 3 real events over course of a week

Front 10

What were results of Wade et al., 2002 study?

Back 10

Narratives were more likely to produce false memory reports than photos

- Perhaps because they promote more familiarity

Front 11

Who studied false memories in 2001 and how?

Back 11

Cabeza et al., 2001

1. Subjects watched videotape segment in which 2 speakers alternatively presented lists of associated words

2. Subjects then performed a recognition test includingwords presented in the study lists (True items), new wordsclosely related to studied words (False items), and new unrelatedwords (New items).

While under fMRI

Front 12

What were Cabeza et al., 2001 results?

Back 12

1. Dissociation between 2 MTL regions, but hippocampus was similarly activated between true and false items

- Suggests recovery of semantic information

2. Parahippocampal gyrus was more activated for true than false items

- Suggests recovery of perceptual information

3. Bilateral DLPFC more activated for true & false than new items

- Possibly reflects monitoring of retrieved information

4. Left VLPFC more activated for new than true/false items

- Possibly reflects semantic processing

In conclusion, anterior MTL doesn't distinguish from true or false

Posterior MTL does

Front 13

How do you convince someone of false memories?

Back 13

1. Convince the individual that the false event is plausible

2. Lead the individual to believe the false event was personally experienced

3. Create a false memory rich in detail through use of false feedback or manipulations of information

Front 14

What did Morgan et al., 2013 study?

Back 14

How misinformation influences memory of recently experienced, highly stressful events

Front 15

What did the Mogran et al., 2013 study do and find?

Back 15

1. Assessed 800 soldiers after stressful camp with either no misinformation, a misinformation questionaire (during assessment afer release), photographic misinformation (during isolation stress) or video misinformation (after release from POW camp).

2. Introduction of misinformation after the experience negatively affected memory for details of the event (e.g. presence of glasses/weapons)

3. Also affected accuracy of identification of an aggressive interrogator

- 50% exposed to misleading photograph falsely accused different individual as interrogator after interrogation was over

Findings demonstrate that memories for stressful events are highly vulnerable to modification by exposure to misinformation. Even in highly trained subjects.

Front 16

What are the 2 types of memory conformity? What is the difference between them?

Back 16

Public conformity

- Individuals recollection may be altered by social influence resulting in long-lasting, persistent memory errors

Private conformity

- Individuals may choose to outwardly comply, providing an account that fits that of others, but inwardly maintain certitude in their own original memory

Front 17

Who studied memory conformity and what did they do?

Back 17

Edelson et al., 2011

1. Subjects viewed eye-witness style documentary on large screen in groups of 5

2. 3 days later returned to lab individually and completed memory test

- This served as baseline accuracy & confidence before the manipulation stage

3. 4 days later, returned to lab & asked same memory questions while under fMRI

- Manipulation introduced to induce conformity

- Presented with answers they were lead to believe were given by their fellow co-observers & photographs of co-observers provided with answers.

- If participant originally had confident veridical memory in test 1, answers provided by "co-observers" were all false

- No-manipulation condition simply presented an 'X' next to the photos

- Credibility trials given in which different patterns of co-observer answers given

4. 1 week later, return to lab & informed that answers given by co-observers were determined randomly

- Rendered socially conveyed info previously provided as uninformative

5. Participants then asked to perform memory test again based on original memory of the movie

Front 18

What were the Edelson study behavioural results?

Back 18

1. Behavioural data showed that manipulation induced memory errors

- Subjects conformed to majority opinion 68% of the time (gave wrong answer to questions they'd previously answered correctly with high confidence)

- Not due to forgetting since in no-manipulation trial, only 15% of answers were incorrect

2. In 3rd test, 3 types of errors:

- Transient errors = Subjects answered correctly in test 1 & 3, but not test 2 - 59%

- Persistent errors = Correct in test 1 but not 2 & 3 - 40%

- Non-conformity = Correct answer in both 1 & 2

3. When controlled for social affects using computer-generated answers (subjects told this), conformity was much lower ~45% but still higher than without manipulation

Front 19

What were the Edelson study imaging results?

Back 19

1. Increased BOLD response during trials that subsequently resulted in persistent errors compared to transient/non-conformity found in hippocampus (except left posterior part), parahippocampal gyri & amygdala.

2. Comparison of persistent vs transient showed greater activity in MTL, left amygdala, right hippocampus & region bordering left PHG & occipital cortex

3. Comparison of transient vs persistent showed greater activity in bilateral dorsal anterior cingulate cortex (ACC)

- No increased emotional arousal/emotional questions, so that was not the cause

4. Heightened functional connectivity between left amygdala and bilateral anterior hippocampus during trials resulting in persistent errors as opposed to other 2 types

Front 20

What is role of amygdala in memory?

Back 20

1. Social & emotional processing

2. Modulates memory-related hippocampal activity

Front 21

What are the 3 causes of memory disorders mentioned in the lecture?

Back 21

1. Korsakoff Syndrome

2. Bilateral thalamus-infarcts

3. Rupture of Anterior Communicating Artery (ACoA)

Front 22

Where the lesion site of the 3 memory disorder causes?

Back 22

Korsakoff's:

- Thalamus

- Mamillary bodies

- Frontal lobe

Bilateral thalamus-infarcts:

- Anterior & medial nuclei

- Mammillothalamic tract

- Ventral amygdalofugal pathway

Rupture of ACoA:

- Basal Forebrain

- Posterior Orbitofrontal Cortex

Front 23

What are the symptoms of the 3 memory disorders?

Back 23

Korsakoff's & ACoA Rupture:

- Anterograde amnesia

- Retrograde episodic amnesia

- Confabulations

Bilateral thalamus-infarcts:

- Anterograde amnesia

- Short (if any) retrograde amnesia

Front 24

Who studied confabulations in brain-damaged patients and what were results?

Back 24

Turner et al., 2008

1. Orbital, medial & left lateral frontal lobe patients confabulated in response to questions about personal episodic memory

2. Orbital, medial and right lateral frontal lobe patients confabulated in response to questions about orientation to time

Front 25

What is the main area Turner et al., thought were responsible for confabulations?

Back 25

Inferior medial frontal lobe (iMFL)