title: Bidirectional GABAergic control of action potential firing in newborn hippocampal granule cells.
abstract: Newly generated young neurons in the adult hippocampus receive GABAergic synaptic inputs, which are crucial for activity-dependent survival and functional maturation between 1-3 weeks after mitosis. We found synaptically driven action potential (AP) firing in these newborn young cells in adult mice. Although glutamatergic synaptic inputs remained subthreshold, activation of GABAergic synaptic inputs depolarized young neurons and reliably evoked APs. Furthermore, pairing of subthreshold excitatory postsynaptic potentials or somatic current injection with brief bursts of GABAergic inputs revealed efficient GABAergic excitation at conductances of ∼ 1.5 nS, corresponding to the activity of only three or four interneurons. Stronger GABAergic inputs (>4 nS) effectively blocked AP firing via shunting inhibition, which might be important to dynamically control spiking output in both directions. Taken together, GABAergic interneurons differentially recruit newborn young granule cells by supporting either AP generation or shunting inhibition dependent on hippocampal network activity.
authors.affiliation: Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Heigele
authors.affiliation: Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Sultan
authors.affiliation: Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Toni
authors.affiliation: Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: Josef
authors.initials: J
authors.lastname: Bischofberger
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D003594:Cytoplasmic Granules; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D066298:In Vitro Techniques; D007395:Interneurons / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D009415:Nerve Net / Q000166:cytology / Q000502:physiology; D009474:Neurons / Q000502:physiology; D018408:Patch-Clamp Techniques; D011247:Pregnancy; D013569:Synapses / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
chemical_list: D005680:gamma-Aminobutyric Acid