"... Whether active dendrites contribute to the generation of the dual temporal and rate codes characteristic of grid cell output is unknown. We show that dendrites of medial entorhinal cortex neurons are highly excitable and exhibit a supralinear input–output function in vitro, while in vivo recordings reveal membrane potential signatures consistent with recruitment of active dendritic conductances. By incorporating these nonlinear dynamics into grid cell models, we show that they can sharpen the precision of the temporal code and enhance the robustness of the rate code, thereby supporting a stable, accurate representation of space under varying environmental conditions. Our results suggest that active dendrites may therefore constitute a key cellular mechanism for ensuring reliable spatial navigation."
Model Type: Synapse
Region(s) or Organism(s): Entorhinal cortex
Cell Type(s): Entorhinal cortex stellate cell; Abstract integrate-and-fire leaky neuron
Currents: I h; I K; I Na,t; I_AHP; I A
Model Concept(s): Spatial Navigation; Dendritic Action Potentials; Active Dendrites; Parameter Fitting; Attractor Neural Network; Synaptic noise
Simulation Environment: NEURON (web link to model); Brian (web link to model); C or C++ program (web link to model)
Implementer(s): Schmidt-Hieber, Christoph [c.schmidt-hieber at ucl.ac.uk]
References:
Schmidt-Hieber C et al. (2017). Active dendritic integration as a mechanism for robust and precise grid cell firing. Nature neuroscience. 20 [PubMed]