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Ca 2+ imaging of mouse neocortical interneurone dendrites: Ia‐type K + channels control action potential backpropagation
Author(s) -
Goldberg Jesse H.,
Tamas Gabor,
Yuste Rafael
Publication year - 2003
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2003.00049.x
Subject(s) - dendritic spike , neuroscience , parvalbumin , calcium imaging , neocortex , calcium , dendritic spine , excitatory postsynaptic potential , gabaergic , backpropagation , voltage dependent calcium channel , biology , chemistry , computer science , artificial neural network , inhibitory postsynaptic potential , artificial intelligence , organic chemistry , hippocampal formation
GABAergic interneurones are essential in cortical processing, yet the functional properties of their dendrites are still poorly understood. In this first study, we combined two‐photon calcium imaging with whole‐cell recording and anatomical reconstructions to examine the calcium dynamics during action potential (AP) backpropagation in three types of V1 supragranular interneurones: parvalbumin‐positive fast spikers (FS), calretinin‐positive irregular spikers (IS), and adapting cells (AD). Somatically generated APs actively backpropagated into the dendritic tree and evoked instantaneous calcium accumulations. Although voltage‐gated calcium channels were expressed throughout the dendritic arbor, calcium signals during backpropagation of both single APs and AP trains were restricted to proximal dendrites. This spatial control of AP backpropagation was mediated by Ia‐type potassium currents and could be mitigated by by previous synaptic activity. Further, we observed supralinear summation of calcium signals in synaptically activated dendritic compartments. Together, these findings indicate that in interneurons, dendritic AP propagation is synaptically regulated. We propose that interneurones have a perisomatic and a distal dendritic functional compartment, with different integrative functions.