title: Hippocampal Theta Input to the Amygdala Shapes Feedforward Inhibition to Gate Heterosynaptic Plasticity.
abstract: The dynamic interactions between hippocampus and amygdala are critical for emotional memory. Theta synchrony between these structures occurs during fear memory retrieval and may facilitate synaptic plasticity, but the cellular mechanisms are unknown. We report that interneurons of the mouse basal amygdala are activated during theta network activity or optogenetic stimulation of ventral CA1 pyramidal cell axons, whereas principal neurons are inhibited. Interneurons provide feedforward inhibition that transiently hyperpolarizes principal neurons. However, synaptic inhibition attenuates during theta frequency stimulation of ventral CA1 fibers, and this broadens excitatory postsynaptic potentials. These effects are mediated by GABAB receptors and change in the Cl(-) driving force. Pairing theta frequency stimulation of ventral CA1 fibers with coincident stimuli of the lateral amygdala induces long-term potentiation of lateral-basal amygdala excitatory synapses. Hence, feedforward inhibition, known to enforce temporal fidelity of excitatory inputs, dominates hippocampus-amygdala interactions to gate heterosynaptic plasticity. VIDEO ABSTRACT.
authors.affiliation: MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK.
authors.forename: Michaël
authors.initials: M
authors.lastname: Bazelot
authors.affiliation: MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK.
authors.forename: Marco
authors.initials: M
authors.lastname: Bocchio
authors.affiliation: Department of Pharmacology, Innsbruck Medical University, Peter Mayr Straße 1a, 6020 Innsbruck, Austria.
authors.forename: Yu
authors.initials: Y
authors.lastname: Kasugai
authors.affiliation: Department of Pharmacology, Innsbruck Medical University, Peter Mayr Straße 1a, 6020 Innsbruck, Austria.
authors.forename: David
authors.initials: D
authors.lastname: Fischer
authors.affiliation: MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Dodson
authors.affiliation: Department of Pharmacology, Innsbruck Medical University, Peter Mayr Straße 1a, 6020 Innsbruck, Austria.
authors.forename: Francesco
authors.initials: F
authors.lastname: Ferraguti
authors.affiliation: MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK. Electronic address: marco.capogna@pharm.ox.ac.uk.
authors.forename: Marco
authors.initials: M
authors.lastname: Capogna
mesh_terms: D000679:Amygdala / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D006624:Hippocampus / Q000502:physiology* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009433:Neural Inhibition / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure; D013826:Theta Rhythm / Q000502:physiology*