title: Dendritic integration in hippocampal dentate granule cells.
abstract: Hippocampal granule cells are important relay stations that transfer information from the entorhinal cortex into the hippocampus proper. This process is critically determined by the integrative properties of granule cell dendrites. However, their small diameter has so far hampered efforts to examine their properties directly. Using a combination of dual somatodendritic patch-clamp recordings and multiphoton glutamate uncaging, we now show that the integrative properties of granule cell dendrites differ substantially from other principal neurons. Due to a very strong dendritic voltage attenuation, the impact of individual synapses on granule cell output is low. At the same time, integration is linearized by voltage-dependent boosting mechanisms, only weakly affected by input synchrony, and independent of input location. These experiments establish that dentate granule cell dendritic properties are optimized for linear integration and strong attenuation of synaptic input from the entorhinal cortex, which may contribute to the sparse activity of granule cells in vivo.
authors.affiliation: Laboratory for Cognition Research and Experimental Epileptology, Department of Epileptology, University of Bonn, Sigmund-Freud-Straße 25, 53105 Bonn, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Krueppel
authors.forename: Stefan
authors.initials: S
authors.lastname: Remy
authors.forename: Heinz
authors.initials: H
authors.lastname: Beck
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D003198:Computer Simulation / Q000706:statistics & numerical data; D003712:Dendrites / Q000502:physiology*; D018891:Dentate Gyrus / Q000166:cytology / Q000502:physiology*; D004594:Electrophysiology / Q000379:methods; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D008853:Microscopy / Q000379:methods; D018408:Patch-Clamp Techniques / Q000379:methods; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000502:physiology*