Research
How do memories change over time in the brain?
When we remember a past experience, we re-create, or ‘reinstate’, the pattern of activity in the brain that was created during our original experience. However, over time, memories undergo many changes – we might forget small, peripheral details of events, while integrating experiences that were related or overlapping. For instance, you may not remember every time you’ve visited your favorite restaurant, but you can probably recall how your favorite dish tastes. These changes in memory may be characterized by changes in the patterns of activity that are reinstated during remembering. I use pattern similarity analyses to examine (1) how memories are reinstated in the brain, and (2) how consolidation changes the reinstatement of memories over time.
Tompary A, Duncan K, Davachi L (2016) High-resolution investigation of memory-specific reinstatement in the hippocampus and perirhinal cortex. Hippocampus 26, 995-1007.
Danker J, Tompary A, Davachi L (2017) Trial-by-trial hippocampal encoding activation predicts the fidelity of cortical reinstatement during subsequent retrieval. Cereb Cortex 7, 3515-24.
Tompary A & Davachi L (2017) Consolidation promotes the emergence of representational overlap in the hippocampus and medial prefrontal cortex. Neuron 96, 228-241.e5.
Tompary A & Davachi L (2022) Consolidation-dependent behavioral integration of sequences related to mPFC neural overlap and hippocampal-cortical connectivity. BioRxiv
What aspects of our experience are prioritized by consolidation?
Memory consolidation is the process by which the brain strengthens (and changes) new memories. One potential mechanism underlying this process is evidence of ‘replay’ in rodents, where neurons involved in encoding of an experience fire again during post-learning periods of sleep and rest. But not all memories are reactivated equally. Instead, this replay process may selectively prioritize elements of a recent experience. To examine which features are preferentially reactivated, I use fMRI to measure post-encoding functional connectivity (e.g. correlations in BOLD signal) between regions that support memory consolidation. I use this approach to characterize the elements of our recent experience that are prioritized by consolidation.
Tompary A*, Duncan K*, Davachi L (2015) Consolidation of associative and item memory is related to post-encoding functional connectivity between the ventral tegmental area and different medial temporal lobe subregions during an unrelated task. J Neurosci 35, 7326-31.
Murty VP, Tompary A, Adcock RA, Davachi L (2017) Selectivity in post-encoding connectivity with high-level visual cortex is associated with reward-motivated memory. J Neurosci 37, 537-45.
Tompary A & Davachi L (2017) Consolidation promotes the emergence of representational overlap in the hippocampus and medial prefrontal cortex. Neuron 96, 228-241.e5.
Goldfarb EV, Tompary A, Davachi L, Phelps EA (2018) Acute stress throughout the memory cycle: Diverging effects on associative and item memory. JEP:G 148, 13-29. PDF Supplement Data
How does prior knowledge interact with new memories?
Virtually every new experience that we undergo is made up of re-combinations of people, places, and things that we have previously encountered. At the same time, new knowledge is thought to emerge over time through the accumulation of information shared across overlapping experiences. How does prior knowledge shape new memory formation, and how does what we already know interact what we’ve recently experienced to build new knowledge?
Tompary A, Zhou W, Davachi L (2020) Schematic memories develop quickly, but are not expressed unless necessary. Scientific Reports 10, 16968
Tompary A & Thompson-Schill SL (2021) Semantic influences on memory distortions. JEP:G
Zeng T, Tompary A, Schapiro AC, Thompson-Schill SL (2021) Tracking the relation between gist and item memory over the course of long-term memory consolidation. eLife
Tompary A, Xia A, Coslett HB, Thompson-Schill SL (in press) Disruption of anterior temporal lobe reduces distortions in memory from category knowledge. JOCN