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Autobiographical memory retrieval and hippocampal activation as a function of repetition and the passage of time.

Nadel L, Campbell J, Ryan L - Neural Plast. (2007)

Bottom Line: While undergoing fMRI scanning, participants retrieved remote autobiographical memories that had been previously retrieved either one month earlier, two days earlier, or multiple times during the preceding month.While all three retrieval conditions activated a similar set of brain regions normally associated with autobiographical memory retrieval including medial temporal lobe structures, hippocampal activation did not change as a function of either multiple retrievals or the passage of time.These results have important implications for existing theories of long-term memory consolidation.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Arizona, Tucson, AZ 85721, USA.

ABSTRACT
Multiple trace theory (MTT) predicts that hippocampal memory traces expand and strengthen as a function of repeated memory retrievals. We tested this hypothesis utilizing fMRI, comparing the effect of memory retrieval versus the mere passage of time on hippocampal activation. While undergoing fMRI scanning, participants retrieved remote autobiographical memories that had been previously retrieved either one month earlier, two days earlier, or multiple times during the preceding month. Behavioral analyses revealed that the number and consistency of memory details retrieved increased with multiple retrievals but not with the passage of time. While all three retrieval conditions activated a similar set of brain regions normally associated with autobiographical memory retrieval including medial temporal lobe structures, hippocampal activation did not change as a function of either multiple retrievals or the passage of time. However, activation in other brain regions, including the precuneus, lateral prefrontal cortex, parietal cortex, lateral temporal lobe, and perirhinal cortex increased after multiple retrievals, but was not influenced by the passage of time. These results have important implications for existing theories of long-term memory consolidation.

Show MeSH
Mean detail measures across retrieval session for multiple and singleretrieval conditions. Mean word count(a) and mean total memory detail count (b) significantly increased betweenDay 1 and Day 28 for the multiple retrieval condition but not for the singleretrieval condition. Mean editorialdetail count (c) was significantly different between the multiple and singleretrieval conditions on Day 1 and between Day 1 and Day 28 for both themultiple and single conditions.
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Related In: Results  -  Collection


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fig3: Mean detail measures across retrieval session for multiple and singleretrieval conditions. Mean word count(a) and mean total memory detail count (b) significantly increased betweenDay 1 and Day 28 for the multiple retrieval condition but not for the singleretrieval condition. Mean editorialdetail count (c) was significantly different between the multiple and singleretrieval conditions on Day 1 and between Day 1 and Day 28 for both themultiple and single conditions.


Autobiographical memory retrieval and hippocampal activation as a function of repetition and the passage of time.

Nadel L, Campbell J, Ryan L - Neural Plast. (2007)

Mean detail measures across retrieval session for multiple and singleretrieval conditions. Mean word count(a) and mean total memory detail count (b) significantly increased betweenDay 1 and Day 28 for the multiple retrieval condition but not for the singleretrieval condition. Mean editorialdetail count (c) was significantly different between the multiple and singleretrieval conditions on Day 1 and between Day 1 and Day 28 for both themultiple and single conditions.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2233815&req=5

fig3: Mean detail measures across retrieval session for multiple and singleretrieval conditions. Mean word count(a) and mean total memory detail count (b) significantly increased betweenDay 1 and Day 28 for the multiple retrieval condition but not for the singleretrieval condition. Mean editorialdetail count (c) was significantly different between the multiple and singleretrieval conditions on Day 1 and between Day 1 and Day 28 for both themultiple and single conditions.
Bottom Line: While undergoing fMRI scanning, participants retrieved remote autobiographical memories that had been previously retrieved either one month earlier, two days earlier, or multiple times during the preceding month.While all three retrieval conditions activated a similar set of brain regions normally associated with autobiographical memory retrieval including medial temporal lobe structures, hippocampal activation did not change as a function of either multiple retrievals or the passage of time.These results have important implications for existing theories of long-term memory consolidation.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Arizona, Tucson, AZ 85721, USA.

ABSTRACT
Multiple trace theory (MTT) predicts that hippocampal memory traces expand and strengthen as a function of repeated memory retrievals. We tested this hypothesis utilizing fMRI, comparing the effect of memory retrieval versus the mere passage of time on hippocampal activation. While undergoing fMRI scanning, participants retrieved remote autobiographical memories that had been previously retrieved either one month earlier, two days earlier, or multiple times during the preceding month. Behavioral analyses revealed that the number and consistency of memory details retrieved increased with multiple retrievals but not with the passage of time. While all three retrieval conditions activated a similar set of brain regions normally associated with autobiographical memory retrieval including medial temporal lobe structures, hippocampal activation did not change as a function of either multiple retrievals or the passage of time. However, activation in other brain regions, including the precuneus, lateral prefrontal cortex, parietal cortex, lateral temporal lobe, and perirhinal cortex increased after multiple retrievals, but was not influenced by the passage of time. These results have important implications for existing theories of long-term memory consolidation.

Show MeSH