fMRI exploration of mind-wandering and memory consolidation
Year: 2025
Type: dissertation
Abstract: 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.
DOI: 10.17918/00011184
Authors: Devayani Joshi, Alexa Tompary
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: gold
OpenAlex ID: W4414404272