@article{14887,
  abstract     = {Episodic memories are encoded by experience-activated neuronal ensembles that remain necessary and sufficient for recall. However, the temporal evolution of memory engrams after initial encoding is unclear. In this study, we employed computational and experimental approaches to examine how the neural composition and selectivity of engrams change with memory consolidation. Our spiking neural network model yielded testable predictions: memories transition from unselective to selective as neurons drop out of and drop into engrams; inhibitory activity during recall is essential for memory selectivity; and inhibitory synaptic plasticity during memory consolidation is critical for engrams to become selective. Using activity-dependent labeling, longitudinal calcium imaging and a combination of optogenetic and chemogenetic manipulations in mouse dentate gyrus, we conducted contextual fear conditioning experiments that supported our model’s predictions. Our results reveal that memory engrams are dynamic and that changes in engram composition mediated by inhibitory plasticity are crucial for the emergence of memory selectivity.},
  author       = {Feitosa Tomé, Douglas and Zhang, Ying and Aida, Tomomi and Mosto, Olivia and Lu, Yifeng and Chen, Mandy and Sadeh, Sadra and Roy, Dheeraj S. and Clopath, Claudia},
  issn         = {1546-1726},
  journal      = {Nature Neuroscience},
  pages        = {561--572},
  publisher    = {Springer Nature},
  title        = {{Dynamic and selective engrams emerge with memory consolidation}},
  doi          = {10.1038/s41593-023-01551-w},
  volume       = {27},
  year         = {2024},
}

@article{17092,
  abstract     = {Memories are thought to be stored in neural ensembles known as engrams that are specifically reactivated during memory recall. Recent studies have found that memory engrams of two events that happened close in time tend to overlap in the hippocampus and the amygdala, and these overlaps have been shown to support memory linking. It has been hypothesized that engram overlaps arise from the mechanisms that regulate memory allocation itself, involving neural excitability, but the exact process remains unclear. Indeed, most theoretical studies focus on synaptic plasticity and little is known about the role of intrinsic plasticity, which could be mediated by neural excitability and serve as a complementary mechanism for forming memory engrams. Here, we developed a rate-based recurrent neural network that includes both synaptic plasticity and neural excitability. We obtained structural and functional overlap of memory engrams for contexts that are presented close in time, consistent with experimental and computational studies. We then investigated the role of excitability in memory allocation at the network level and unveiled competitive mechanisms driven by inhibition. This work suggests mechanisms underlying the role of intrinsic excitability in memory allocation and linking, and yields predictions regarding the formation and the overlap of memory engrams.},
  author       = {Delamare, Geoffroy and Feitosa Tomé, Douglas and Clopath, Claudia},
  issn         = {1529-2401},
  journal      = {Journal of Neuroscience},
  number       = {21},
  publisher    = {Society for Neuroscience},
  title        = {{Intrinsic neural excitability biases allocation and overlap of memory engrams}},
  doi          = {10.1523/JNEUROSCI.0846-23.2024},
  volume       = {44},
  year         = {2024},
}

@misc{14892,
  abstract     = {Code and data necessary to reproduce the simulations and data analyses reported in our manuscript: Tomé, D.F., Zhang, Y., Aida, T., Mosto, O., Lu, Y., Chen, M., Sadeh, S., Roy, D. S., Clopath, C. Dynamic and selective engrams emerge with memory consolidation. 2023.},
  author       = {Feitosa Tomé, Douglas},
  publisher    = {Zenodo},
  title        = {{douglastome/dynamic-engrams: Dynamic and selective engrams emerge with memory consolidation}},
  doi          = {10.5281/ZENODO.10251087},
  year         = {2023},
}