arXiv Machine Learning

Embedding of Low-Dimensional Sensory Dynamics in Recurrent Networks: Implications for the Geometry of Neural Representation

arXiv:2601. 19019v3 Announce Type: replace-cross Abstract: Neural population activity in sensory cortex is organized on low-dimensional manifolds, but why such manifolds arise and what determines their geometry remain unclear.

arXiv AI
Aug 25

Divisive Normalization Shapes Low-Rank Slow Manifolds for Continuous Working Memory

The paper introduces the Recurrent Divisive Normalization Network (RDNN), a minimal model that incorporates divisive normalization—a common neural computation—to stabilize continuous working memory representations. Dynamical systems analysis shows that this biophysical constraint enables the network to converge to robust, high‑fidelity slow manifolds, while gradient dynamics during Backpropagation Through Time reveal an activity‑dependent local scaling that compresses the network’s effective rank into a low‑dimensional subspace. Ablation studies confirm that divisive normalization, rather than subtractive inhibition, is essential for preventing manifold shattering under time‑varying inputs.

By Zhaotian Gu, Jie Su, Weiwei Wang, Chang Liu, Tianyi Qian, Dahui Wang
arXiv Machine Learning
Aug 19

Center-Manifold Reduction of Learning at Bifurcations: Interference and Rich Learning in Recurrent Neural Networks

The paper investigates how gradient descent behaves near codimension‑one bifurcations in recurrent neural networks by analyzing the global empirical Neural Tangent Kernel (GeNTK). Under local center‑manifold conditions, the parameter‑to‑state Jacobian is approximated by a low‑rank normal‑form operator, causing the GeNTK and Fisher information matrix to become strongly amplified and anisotropic, concentrating on a rank‑one or rank‑two channel depending on the bifurcation type. Experiments on high‑dimensional RNNs confirm that this low‑rank concentration coincides with abrupt loss changes, subtask interference, and aligns with changes in memory dynamics in a 15‑task LeakyRNN.

By James Hazelden, Eric Shea-Brown
arXiv AI
Sep 25

ELiSe: Efficient Learning of Sequences in Structured Recurrent Networks

The paper introduces ELiSe, a model that leverages cortical network scaffolds and dendritic compartments to learn complex non‑Markovian spatio‑temporal patterns using only local, always‑on, phase‑free synaptic plasticity. It demonstrates the model’s ability to acquire and replay intricate sequences, exemplified by a birdsong learning mock‑up, and shows robustness to external disturbances and flexibility in parameter settings.

By Laura Kriener, Kristin V\"olk, Ben von H\"unerbein, Federico Benitez, Walter Senn, Mihai A. Petrovici