Balancing Stability and Flow in Hippocampal Networks via Inductive Bias and Learned Symmetry Breaking
Journal:
bioRxiv
Published Date:
Feb 9, 2026
Abstract
The hippocampus must balance stable memory representations with internally generated sequential dynamics underlying replay, prediction and traveling waves. How hippocampal circuitry achieves both remains unclear. Here, we show that recurrent neural networks trained on continuous prediction tasks converge to a mixed-symmetry dynamical regime, in which dominant symmetric recurrence stabilizes a continuous attractor while a weaker antisymmetric component induces directed flow along it. Symmetry breaking occurs in physical systems such as the ferromagnetic phase transition between ordered and disordered states. This structure accelerates learning and supports robust replay and prediction. We further show that such symmetry breaking can arise from biologically plausible spike-timing-dependent plasticity (STDP) rules, yielding a tilted Mexican-hat connectivity profile without explicit architectural constraints. Importantly, initializing networks with CA3-like structured connectivity biases learning toward this regime, improving optimization efficiency and performance. These results suggest that hippocampal computation reflects an interaction between biologically constrained circuit structure and task-driven learning, with partial symmetry breaking providing a low-dimensional control principle for balancing stability and flow in sequence generation.
