Morpho-physiological criteria divide dentate gyrus interneurons into classes

Hippocampus. 2014 Feb;24(2):189-203. doi: 10.1002/hipo.22214.


GABAergic inhibitory interneurons control fundamental aspects of neuronal network function. Their functional roles are assumed to be defined by the identity of their input synapses, the architecture of their dendritic tree, the passive and active membrane properties and finally the nature of their postsynaptic targets. Indeed, interneurons display a high degree of morphological and physiological heterogeneity. However, whether their morphological and physiological characteristics are correlated and whether interneuron diversity can be described by a continuum of GABAergic cell types or by distinct classes has remained unclear. Here we perform a detailed morphological and physiological characterization of GABAergic cells in the dentate gyrus, the input region of the hippocampus. To achieve an unbiased and efficient sampling and classification we used knock-in mice expressing the enhanced green fluorescent protein (eGFP) in glutamate decarboxylase 67 (GAD67)-positive neurons and performed cluster analysis. We identified five interneuron classes, each of them characterized by a distinct set of anatomical and physiological parameters. Cross-correlation analysis further revealed a direct relation between morphological and physiological properties indicating that dentate gyrus interneurons fall into functionally distinct classes which may differentially control neuronal network activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Bicuculline / analogs & derivatives
  • Bicuculline / pharmacology
  • Calbindin 2 / metabolism
  • Calbindins / metabolism
  • Cluster Analysis
  • Dentate Gyrus / cytology*
  • Electric Stimulation
  • Excitatory Amino Acid Antagonists / pharmacology
  • GABA-A Receptor Antagonists / pharmacology
  • Glutamate Decarboxylase / genetics
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • In Vitro Techniques
  • Interneurons / classification*
  • Interneurons / drug effects
  • Interneurons / physiology*
  • Kynurenic Acid / pharmacology
  • Membrane Potentials / drug effects
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic


  • Calbindin 2
  • Calbindins
  • Excitatory Amino Acid Antagonists
  • GABA-A Receptor Antagonists
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • bicuculline methiodide
  • Glutamate Decarboxylase
  • glutamate decarboxylase 1
  • Kynurenic Acid
  • Bicuculline