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Building memories remembering and forgetting of
verbal experiences as predicted by brain activity
Building memories remembering and forgetting of
verbal experiences as predicted by brain activity
Anthony D. Wagner, Daniel L. Schacter, Michael Rotte, Wilma Koutstaal, Anat Maril, Anders M. Dale, Bruce R. Rosen, Randy L.
BucknerBy: Andrea Ching
Anthony D. Wagner, Daniel L. Schacter, Michael Rotte, Wilma Koutstaal, Anat Maril, Anders M. Dale, Bruce R. Rosen, Randy L.
BucknerBy: Andrea Ching
BackgroundBackground
What is memory encoding? Memory encoding refers to the
processes by which an experience is transformed into an enduring memory trace.
What is memory encoding? Memory encoding refers to the
processes by which an experience is transformed into an enduring memory trace.
BackgroundBackground
Memorability of an event is influenced by the cognitive operations during the initial encoding of the event.
Semantic processing>Nonsemantic processing
Memorability of an event is influenced by the cognitive operations during the initial encoding of the event.
Semantic processing>Nonsemantic processing
BackgroundBackground
Left pre-frontal cortex involved in verbal encoding
Left pre-frontal cortex activation greater in semantic relative to non-semantic encoding.
Left pre-frontal cortex involved in verbal encoding
Left pre-frontal cortex activation greater in semantic relative to non-semantic encoding.
BackgroundBackground
Medial temporal regionsLesion studies
No medial temporal activationNeuroimaging studies
Parahippocampal gyrus Novel stimuli > familiar stimuli
Medial temporal regionsLesion studies
No medial temporal activationNeuroimaging studies
Parahippocampal gyrus Novel stimuli > familiar stimuli
Method-First ExperimentMethod-First Experiment
Twelve normal, right handed subjects
Seven men, five women Aged 18-29 years
Twelve normal, right handed subjects
Seven men, five women Aged 18-29 years
Method-First ExperimentMethod-First Experiment
Blocked design experimentTrials from each encoding condition
are presented sequentially inseparable from each other during the scan
Comparison between activation during semantic vs non-semantic processing task
Blocked design experimentTrials from each encoding condition
are presented sequentially inseparable from each other during the scan
Comparison between activation during semantic vs non-semantic processing task
Method-First ExperimentMethod-First Experiment
Alternating task-blocksSemantic processingNon-semantic processingVisual fixation
Novelty of the words are equivalent in semantic and non-semantic blocks.
Alternating task-blocksSemantic processingNon-semantic processingVisual fixation
Novelty of the words are equivalent in semantic and non-semantic blocks.
Method-First ExperimentMethod-First Experiment
During semantic and nonsemantic blocks, 20 words were visually presented: 10 abstract and 10 concrete nouns; half in uppercase and half in lowercase letters.
Each word was presented for 1 s followed by 1 s of fixation between words.
Memory was assessed using a yes-no recognition procedure after 20 to 40 minutes
During semantic and nonsemantic blocks, 20 words were visually presented: 10 abstract and 10 concrete nouns; half in uppercase and half in lowercase letters.
Each word was presented for 1 s followed by 1 s of fixation between words.
Memory was assessed using a yes-no recognition procedure after 20 to 40 minutes
Results-First ExperimentResults-First Experiment
Reaction times were longer for semantic decisions
Subsequent memory was superior following semantic (85% recognized) than following non-semantic processing(47% recognized).
Reaction times were longer for semantic decisions
Subsequent memory was superior following semantic (85% recognized) than following non-semantic processing(47% recognized).
Greater Activation during Semantic Processing
Greater Activation during Semantic Processing
Method-Second Experiment
Method-Second Experiment
Thirteen normal, right-handed subjects
Six men and seven women Aged 18-35 years
Thirteen normal, right-handed subjects
Six men and seven women Aged 18-35 years
Method-Second Experiment
Method-Second Experiment
Event-related fMRI was used while participants performed a single incidental encoding task.
Word and fixation events presented in a continuous series of 120 intermixed trials.
Semantic decision during word trials(abstract or concrete).
Recognition test (High or low confidence).
Event-related fMRI was used while participants performed a single incidental encoding task.
Word and fixation events presented in a continuous series of 120 intermixed trials.
Semantic decision during word trials(abstract or concrete).
Recognition test (High or low confidence).
Method-Second Experiment
Method-Second Experiment
fMRI data analysis: four encoding trial typesHigh confidence hitsLow confidence hitsMissesFixation
fMRI data analysis: four encoding trial typesHigh confidence hitsLow confidence hitsMissesFixation
Results-Second Experiment
Results-Second Experiment
Word processing relative to fixation resulted in greater activation
High confidence hits to missesMultiple left prefrontal regionsLeft parahippocampal gyrusFusiform gyrus
Word processing relative to fixation resulted in greater activation
High confidence hits to missesMultiple left prefrontal regionsLeft parahippocampal gyrusFusiform gyrus
DiscussionDiscussion
Magnitude of activation is greater in remembered eventsSubsequently remembered events are
processed longer during learning Reaction times for high confidence hits
and miss trials were matchedGreater activation in left prefrontal and
temporal regions in subsequently remembered items
Magnitude of activation is greater in remembered eventsSubsequently remembered events are
processed longer during learning Reaction times for high confidence hits
and miss trials were matchedGreater activation in left prefrontal and
temporal regions in subsequently remembered items
DiscussionDiscussion
Left parahippocampal gyrus is more active in later remembered events even though both were equally novel
Extends beyond novelty detectionmore general encoding mechanism
Principal neocortical input to hippocampal regionimportant role in memory formation
Left parahippocampal gyrus is more active in later remembered events even though both were equally novel
Extends beyond novelty detectionmore general encoding mechanism
Principal neocortical input to hippocampal regionimportant role in memory formation
ConclusionConclusion
Verbal experience may be more memorable when semantic and phonological attributes are processed via the left prefrontal regions.
Organization in working memory serves as input to the parahippocampal gyrus and the medial temporal memory system.
Left prefrontal and temporal processes will tend to produce more memorable verbal events.
Verbal experience may be more memorable when semantic and phonological attributes are processed via the left prefrontal regions.
Organization in working memory serves as input to the parahippocampal gyrus and the medial temporal memory system.
Left prefrontal and temporal processes will tend to produce more memorable verbal events.
StrengthsStrengths
Limited confoundsReaction times
Were able to identify many brain regions that were involved in remembering
Limited confoundsReaction times
Were able to identify many brain regions that were involved in remembering
LimitationsLimitations
Small sample size Small sample size
Future ResearchFuture Research
Instead of words they could use pictures
Age, sex differences
Instead of words they could use pictures
Age, sex differences
ReferencesReferences
Wagner AD, Schacter DL, Rotte M, Koutstaal W, Maril A, Dale
AM, Rosen BR, Buckner RL (1998) Building memories: remembering and forgetting of verbal experiences as predicted by brain
activity. Science, 281(5350), 1188 –1191.
Wagner AD, Schacter DL, Rotte M, Koutstaal W, Maril A, Dale
AM, Rosen BR, Buckner RL (1998) Building memories: remembering and forgetting of verbal experiences as predicted by brain
activity. Science, 281(5350), 1188 –1191.
