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Séminaire impromptu - Jason ChristieLocal control of spike signaling within unmyelinated axons

Abstract :

 The fundamental function of an axon is
to permit the cell-to-cell transfer of neuronal information by way of action potentials (APs) at presynaptic sites of release. It is well known that, in myelinated axons of projection neurons, fast salutatory conduction ensures that APs are rapidly propagated to release sites in a stereotyped manner ensuring a reliable trigger for neurotransmission. In comparison, AP signaling in the unmyelinated axons of compact interneurons is poorly understood. In this seminar, I will present our recent findings from cerebellar interneurons indicating that the location-specific distribution (i.e. “nodal arrangement”) of fast activating voltage-dependent potassium (Kv) channels at individual boutons confers highly-localized control of axonal excitation and release. In this way, enabling compartmentalized organization of axonal electrogenesis and local tuning of spike shape in a synapse-by-synapse manner thus adding an extra dimension to synaptic signaling and plasticity.

Selected publications

Rowan M.J., Tranquil E., Christie J.M. (2014). Distinct Kv channel subtypes contribute to differences in spike signaling properties in the axon initial segment and presynaptic boutons of cerebellar interneurons. J. Neurosci. 34(19):6611-23.

Christie, J.M., Chiu, D.N., Jahr, C.E. (2011). Ca2+-dependent enhancement of release by subthreshold somatic depolarization. Nat. Neurosci. 14: 62-68.

Christie, J.M. and Jahr, C.E. (2009). Selective expression of ligand-gated ion channels in L5 pyramidal cell axons. J. Neurosci. 29: 11441-11450.

Christie, J.M. and Jahr, C.E. (2008). Dendritic NMDA receptors activate axonal calcium channels. Neuron. 60: 298-307.

Christie, J.M. and Westbrook, G.L. (2006). Lateral excitation within the olfactory bulb. J. Neurosci. 26: 2269-2277.

Scientific focus :

Researcher Bio
Dr. Christie joined the Max Planck Florida Institute in July 2010 as Research Group Leader in Synaptic Signaling and Computation. Prior to this appointment, Dr. Christie conducted research at the Vollum Institute at the Oregon Health and Science University in Portland, Oregon, where he completed his doctoral and post-doctoral work. While at the Vollum Institute, he was awarded a National Research Service Award. He currently serves as an ad hoc editor for the Journal of Neurophysiology and the Journal of Neuroscience and is also a member of the Society for Neuroscience. He has joint faculty appointments with Scripps Florida and Florida Atlantic University.