The global spike: conserved dendritic properties enable unique Ca2+ spike generation in low threshold spiking neurons.
William M Connelly, Vincenzo Crunelli & Adam C Errington
(2015) The Journal of Neuroscience, 35(47) 15505-15522. see also This Week in the Journal, The Journal of Neuroscience 35(47), i.
Our latest work on the dendritic properties of thalamocortical (TC) and thalamic reticular nucleus (TRN) neurons has been published in The Journal of Neuroscience. In this paper we describe the mechanism that underlies the generation of low threshold spikes (LTS) in TC and TRN neurons. We show how the electrical properties of dendrites are highly conserved between these cells and how they are essential for the generation of LTS. For the first time we performed direct electrical recordings from the thin dendrites of TC and TRN neurons. We find that the dendrites of these two different types of neuron share a number of important dendritic properties that are necessary for their ability to generate LTS. In particular, these neurons are very electrotonically compact from the viewpoint of the soma and the entire dendritic tree can be depolarized in unison to recruit dendritic T-type Ca2+ channels that are widely distributed in physical space. We show that the mechanisms underlying the LTS in LT-spiking neurons means that it is generated in a markedly different manner to other neuronal spikes including sodium mediated action potentials, dendritic Ca2+ spikes and NMDA spike/plateaus.