Li, Yiding, John J. Briguglio, Sandro Romani, Jeffrey C. Magee, Eddy Kinganda-Lusamaki, Adrienne Amuri-Aziza, Nicolas Fernandez-Nuñez et al. “Mechanisms of memory-supporting neuronal dynamics in hippocampal area CA3.” Cell 187 (2024): 2030-2051.

Summary
“Hippocampal CA3 is central to memory formation and retrieval. Although various network mechanisms have been proposed, direct evidence is lacking. Using intracellular Vm recordings and optogenetic manipulations in behaving mice, we found that CA3 place-field activity is produced by a symmetric form of behavioral timescale synaptic plasticity (BTSP) at recurrent synapses among CA3 pyramidal neurons but not at synapses from the dentate gyrus (DG). Additional manipulations revealed that excitatory input from the entorhinal cortex (EC) but not the DG was required to update place cell activity based on the animal’s movement. These data were captured by a computational model that used BTSP and an external updating input to produce attractor dynamics under online learning conditions. Theoretical analyses further highlight the superior memory storage capacity of such networks, especially when dealing with correlated input patterns. This evidence elucidates the cellular and circuit mechanisms of learning and memory formation in the hippocampus.”

Highlights
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•CA3 intracellular Vm recordings and optogenetic manipulations in behaving mice
•Symmetric BTSP at CA3-CA3 recurrent synapses builds attractor dynamics within CA3
•External EC inputs update the CA3 attractor dynamics in accordance with behavior
•A neuronal network built by BTSP possesses superior memory storage capacity

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Li, Yiding, John J. Briguglio, Sandro Romani, Jeffrey C. Magee, Eddy Kinganda-Lusamaki, Adrienne Amuri-Aziza, Nicolas Fernandez-Nuñez et al. “Mechanisms of memory-supporting neuronal dynamics in hippocampal area CA3.” Cell 187 (2024): 2030-2051.