Firing rate adaptation in grid cells produces macroscopic hexadirectional modulation
- 1UCL Institute of Cognitive Neuroscience
Abstract
Hexadirectional modulation (HexMod) of macroscopic neural activity by movement direction is widely used to measure grid cell activity in human neuroimaging, but its neuronal origin is unclear. Two mechanisms have been proposed: conjunctive gridxdirection cells whose preferred directions align with the grid axes, and firing rate adaptation, which reduces firing when grid fields are visited in quick succession during movement along grid axes. Analysing almost 4,000 grid cells from foraging rats, we found that conjunctive cells' directional tuning was broad and unaligned with grid axes, whereas firing was reduced shortly after grid field visits, consistent with firing rate adaptation. Simulations of realistic grid cell populations demonstrate HexMod with the typical trajectories of human experiments, and show how it depends on grid scale, adaptation time constant, movement speed, and controlling for variation with location. We show firing rate adaptation provides a plausible mechanism for HexMod and a framework for relating human neuroimaging to neuronal activity.
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BibTeX
@misc{reggio2026firing,
title = {{Firing rate adaptation in grid cells produces macroscopic hexadirectional modulation}},
author = {G. Reggio and M. Kim and Z. Ji and D. Bush and C. Barry and N. Burgess},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.19.760191},
url = {https://www.biorxiv.org/content/10.64898/2026.10.19.760191v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Firing rate adaptation in grid cells produces macroscopic hexadirectional modulation
AU - G. Reggio
AU - M. Kim
AU - Z. Ji
AU - D. Bush
AU - C. Barry
AU - N. Burgess
PY - 2026
DA - 2026/10/19
PB - bioRxiv
DO - 10.64898/2026.10.19.760191
UR - https://www.biorxiv.org/content/10.64898/2026.10.19.760191v1
AB - Hexadirectional modulation (HexMod) of macroscopic neural activity by movement direction is widely used to measure grid cell activity in human neuroimaging, but its neuronal origin is unclear. Two mechanisms have been proposed: conjunctive gridxdirection cells whose preferred directions align with the grid axes, and firing rate adaptation, which reduces firing when grid fields are visited in quick succession during movement along grid axes. Analysing almost 4,000 grid cells from foraging rats, we found that conjunctive cells' directional tuning was broad and unaligned with grid axes, whereas firing was reduced shortly after grid field visits, consistent with firing rate adaptation. Simulations of realistic grid cell populations demonstrate HexMod with the typical trajectories of human experiments, and show how it depends on grid scale, adaptation time constant, movement speed, and controlling for variation with location. We show firing rate adaptation provides a plausible mechanism for HexMod and a framework for relating human neuroimaging to neuronal activity.
ER -