Dentate gyrus granule cells (GCs) connect the entorhinal cortex to the hippocampal CA3 region, but how they process spatial information remains enigmatic. To examine the role of GCs in spatial coding, we measured excitatory postsynaptic potentials (EPSPs) and action potentials (APs) in head-fixed mice running on a linear belt. Intracellular recording from morphologically identified GCs revealed that most cells were active, but activity level varied over a wide range. Whereas only ∼5% of GCs showed spatially tuned spiking, ∼50% received spatially tuned input. Thus, the GC population broadly encodes spatial information, but only a subset relays this information to the CA3 network. Fourier analysis indicated that GCs received conjunctive place-grid-like synaptic input, suggesting code conversion in single neurons. GC firing was correlated with dendritic complexity and intrinsic excitability, but not extrinsic excitatory input or dendritic cable properties. Thus, functional maturation may control input-output transformation and spatial code conversion.
This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement 692692, P.J.) and the Fond zur Förderung der Wissenschaftlichen Forschung (Z 312-B27, Wittgenstein award, P.J.). We thank Gyorgy Buzsáki, Jozsef Csicsvari, Juan Ramirez Villegas, and Federico Stella for commenting on earlier versions of this manuscript. We also thank Katie Bittner, Michael Brecht, Albert Lee, Jeffery Magee, and Alejandro Pernía-Andrade for sharing expertise in in vivo patch-clamp recording. We are grateful to Florian Marr for cell labeling, cell reconstruction, and technical assistance; Ben Suter for helpful discussions; Christina Altmutter for technical support; Eleftheria Kralli-Beller for manuscript editing; and Todor Asenov (Machine Shop) for device construction. We also thank the Scientific Service Units (SSUs) of IST Austria (Machine Shop, Scientific Computing, and Preclinical Facility) for efficient support.
Zhang X, Schlögl A, Jonas PM. Selective routing of spatial information flow from input to output in hippocampal granule cells. Neuron. 2020;107(6):1212-1225. doi:10.1016/j.neuron.2020.07.006
Zhang, X., Schlögl, A., & Jonas, P. M. (2020). Selective routing of spatial information flow from input to output in hippocampal granule cells. Neuron. Elsevier. https://doi.org/10.1016/j.neuron.2020.07.006
Zhang, Xiaomin, Alois Schlögl, and Peter M Jonas. “Selective Routing of Spatial Information Flow from Input to Output in Hippocampal Granule Cells.” Neuron. Elsevier, 2020. https://doi.org/10.1016/j.neuron.2020.07.006.
X. Zhang, A. Schlögl, and P. M. Jonas, “Selective routing of spatial information flow from input to output in hippocampal granule cells,” Neuron, vol. 107, no. 6. Elsevier, pp. 1212–1225, 2020.
Zhang X, Schlögl A, Jonas PM. 2020. Selective routing of spatial information flow from input to output in hippocampal granule cells. Neuron. 107(6), 1212–1225.
Zhang, Xiaomin, et al. “Selective Routing of Spatial Information Flow from Input to Output in Hippocampal Granule Cells.” Neuron, vol. 107, no. 6, Elsevier, 2020, pp. 1212–25, doi:10.1016/j.neuron.2020.07.006.
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