@article {70164, title = {Place-cell heterogeneity underlies power-laws in hippocampal activity}, journal = {arXiv}, year = {2025}, month = {2025 Jul 30}, abstract = {

Power-law scaling in coarse-grained data suggests critical dynamics, but the true source of this scaling often remains unclear. Here, we analyze neural activity recorded during spatial navigation, reproducing power-law scaling under a phenomenological renormalization group (PRG) procedure that clusters units by activity similarity. Such scaling was previously linked to criticality. Here, we show that the iterative nature of the procedure itself leads to the emergence of power laws when applied to heterogeneous, non-interacting units obeying spatially structured activity without requiring critical interactions. Furthermore, the scaling exponents produced by heteregeneous non-interacting units match the observed exponents in recorded neural data. A simplified version of the PRG further reveals how heterogeneity smooths transitions across scales, mimicking critical behavior. The resulting exponents depend systematically on system and population size, predictions confirmed by subsampling the data.

}, doi = {10.48550/arXiv.2507.23030}, url = {https://arxiv.org/abs/2507.23030}, author = {John J. Briguglio and Jaesung Lee and Albert K. Lee and Vincent Hakim and Sandro Romani} } @article {68793, title = {Mechanisms of memory-supporting neuronal dynamics in hippocampal area CA3}, journal = {Cell}, volume = {S0092-8674}, year = {2024}, month = {2024 Oct 17}, pages = {01141-3}, abstract = {

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{\textquoteright}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.

}, doi = {10.1016/j.cell.2024.09.041}, url = {https://doi.org/10.1016/j.cell.2024.09.041}, author = {Yiding Li and John J. Briguglio and Sandro Romani and Jeffrey C. Magee} }