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The global spike: conserved dendritic properties enable unique Ca2+ spike generation in low-threshold spiking neurons


Connelly, WM and Crunelli, V and Errington, AC, The global spike: conserved dendritic properties enable unique Ca2+ spike generation in low-threshold spiking neurons, Journal of Neuroscience, 35, (47) pp. 15505-15522. ISSN 0270-6474 (2015) [Refereed Article]


Copyright Statement

Copyright 2015 Connelly et al. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.1523/JNEUROSCI.2740-15.2015


Low-threshold Ca2+ spikes (LTS) are an indispensible signaling mechanism for neurons in areas including the cortex, cerebellum, basal ganglia, and thalamus. They have critical physiological roles and have been strongly associated with disorders including epilepsy, Parkinson's disease, and schizophrenia. However, although dendritic T-type Ca2+ channels have been implicated in LTS generation, because the properties of low-threshold spiking neuron dendrites are unknown, the precise mechanism has remained elusive. Here, combining data from fluorescence-targeted dendritic recordings and Ca2+ imaging from low-threshold spiking cells in rat brain slices with computational modeling, the cellular mechanism responsible for LTS generation is established. Our data demonstrate that key somatodendritic electrical conduction properties are highly conserved between glutamatergic thalamocortical neurons and GABAergic thalamic reticular nucleus neurons and that these properties are critical for LTS generation. In particular, the efficiency of soma to dendrite voltage transfer is highly asymmetric in low-threshold spiking cells, and in the somatofugal direction, these neurons are particularly electrotonically compact. Our data demonstrate that LTS have remarkably similar amplitudes and occur synchronously throughout the dendritic tree. In fact, these Ca2+ spikes cannot occur locally in any part of the cell, and hence we reveal that LTS are generated by a unique whole-cell mechanism that means they always occur as spatially global spikes. This all-or-none, global electrical and biochemical signaling mechanism clearly distinguishes LTS from other signals, including backpropagating action potentials and dendritic Ca2+/NMDA spikes, and has important consequences for dendritic function in low-threshold spiking neurons.

Item Details

Item Type:Refereed Article
Keywords:Vision, thalamus, synaptic integration, non-linear systems
Research Division:Biomedical and Clinical Sciences
Research Group:Neurosciences
Research Field:Cellular nervous system
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Connelly, WM (Dr William Connelly)
ID Code:131557
Year Published:2015
Web of Science® Times Cited:21
Deposited By:Medicine
Deposited On:2019-03-22
Last Modified:2019-04-29
Downloads:29 View Download Statistics

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