title: The role of hyperpolarization-activated cationic current in spike-time precision and intrinsic resonance in cortical neurons in vitro.
abstract: Hyperpolarization-activated cyclic nucleotide modulated current (I(h)) sets resonance frequency within the θ-range (5–12 Hz) in pyramidal neurons. However, its precise contribution to the temporal fidelity of spike generation in response to stimulation of excitatory or inhibitory synapses remains unclear. In conditions where pharmacological blockade of I(h) does not affect synaptic transmission, we show that postsynaptic h-channels improve spike time precision in CA1 pyramidal neurons through two main mechanisms. I(h) enhances precision of excitatory postsynaptic potential (EPSP)--spike coupling because I(h) reduces peak EPSP duration. I(h) improves the precision of rebound spiking following inhibitory postsynaptic potentials (IPSPs) in CA1 pyramidal neurons and sets pacemaker activity in stratum oriens interneurons because I(h) accelerates the decay of both IPSPs and after-hyperpolarizing potentials (AHPs). The contribution of h-channels to intrinsic resonance and EPSP waveform was comparatively much smaller in CA3 pyramidal neurons. Our results indicate that the elementary mechanisms by which postsynaptic h-channels control fidelity of spike timing at the scale of individual neurons may account for the decreased theta-activity observed in hippocampal and neocortical networks when h-channel activity is pharmacologically reduced.
authors.affiliation: 1INSERM, U641, Marseille, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Gastrein
authors.forename: Emilie
authors.initials: E
authors.lastname: Campanac
authors.forename: Célia
authors.initials: C
authors.lastname: Gasselin
authors.forename: Robert H
authors.initials: RH
authors.lastname: Cudmore
authors.forename: Andrzej
authors.initials: A
authors.lastname: Bialowas
authors.forename: Edmond
authors.initials: E
authors.lastname: Carlier
authors.forename: Laure
authors.initials: L
authors.lastname: Fronzaroli-Molinieres
authors.forename: Norbert
authors.initials: N
authors.lastname: Ankri
authors.forename: Dominique
authors.initials: D
authors.lastname: Debanne
mesh_terms: D000818:Animals; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000378:metabolism / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D004594:Electrophysiology / Q000379:methods; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D019579:Neocortex / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D015221:Potassium Channels / Q000378:metabolism / Q000502:physiology*; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology*; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D013569:Synapses / Q000187:drug effects / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
chemical_list: D054815:Cyclic Nucleotide-Gated Cation Channels; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D015221:Potassium Channels; D011743:Pyrimidines; C082246:ICI D2788