This thesis examines how spontaneous thought during post-encoding rest contributes to memory consolidation. Using fMRI, I examined hippocampal reactivation, coordinated reactivation with cortical regions, and default mode network (DMN) activity in relation to both mind-wandering and later memory performance. Participants encoded object-scene pairs and then rested for 40 minutes while answering thought probes, and then completed memory tests immediately and a day later. I used multivoxel pattern analysis to detect reactivation in the hippocampus and cortical areas such as the parahippocampal place area and medial prefrontal cortex. Reactivation in the hippocampus and across hippocampal-cortical networks increased after learning, and these events supported immediate recall more than delayed recall. Mind-wandering, by contrast, showed a clear behavioral benefit: participants who reported higher mind-wandering performed better on the cued scene recall task. Also, DMN activity tracked with mind-wandering reports, though its strength was not tied directly to hippocampal reactivation counts. Overall, the findings suggest that post-encoding rest is an active state in which both reactivation and mind-wandering shape memory. Reactivation seemed to provide a short-term boost, while mind-wandering provided a consistent positive association with recall. Together, these results point to complementary roles for the hippocampus, cortex, and DMN in turning recent experience into memory.
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Details
Title
fMRI exploration of mind-wandering and memory consolidation
Creators
Devayani Joshi
Contributors
Alexa Tompary (Advisor)
Awarding Institution
Drexel University
Degree Awarded
Master of Science (M.S.)
Publisher
Drexel University; Philadelphia, Pennsylvania
Number of pages
v, 38 pages
Resource Type
Thesis
Language
English
Academic Unit
Psychological and Brain Sciences (Psychology); College of Arts and Sciences; Drexel University
Other Identifier
991022093253104721
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