Place-cell heterogeneity underlies power-laws in hippocampal activity

TL;DR

This study demonstrates that heterogeneity in place-cell activity can produce power-law scaling in hippocampal data without requiring critical interactions, challenging the interpretation of such scaling as evidence of criticality.

Contribution

The paper shows that power-law scaling in neural activity can arise from heterogeneity and the clustering procedure itself, not necessarily from critical dynamics.

Findings

Power-law scaling emerges from heterogeneity and clustering, not criticality.

Scaling exponents match those observed in neural data.

Heterogeneity influences the scaling behavior and depends on system size.

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.