New methods for quantifying rapidity of action potential onset differentiate neuron types

• Published in: PloS one Vol. 16; no. 4; p. e0247242
• Main Authors: Aldohbeyb, Ahmed A, Vigh, Jozsef, Lear, Kevin L
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 08.04.2021; Public Library of Science (PLoS)
• Subjects: Action potential; Action potentials (Electrophysiology); Biology and Life Sciences; Biomedical engineering; Carbon monoxide; Data analysis; Drafting software; Editing; Engineering; Hippocampus; Identification and classification; Interneurons; Mathematical analysis; Measurement; Measurement techniques; Medicine and Health Sciences; Methods; Neurons; Parvalbumin; Physical Sciences; Physiological aspects; Reviews; Visualization; United States; United States > US; Colorado
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0247242

Two new methods for quantifying the rapidity of action potential onset have lower relative standard deviations and better distinguish neuron cell types than current methods. Action potentials (APs) in most central mammalian neurons exhibit sharp onset dynamics. The main views explaining such an abrupt onset differ. Some studies suggest sharp onsets reflect cooperative sodium channels activation, while others suggest they reflect AP backpropagation from the axon initial segment. However, AP onset rapidity is defined subjectively in these studies, often using the slope at an arbitrary value on the phase plot. Thus, we proposed more systematic methods using the membrane potential's second-time derivative ([Formula: see text]) peak width. Here, the AP rapidity was measured for four different cortical and hippocampal neuron types using four quantification methods: the inverse of full-width at the half maximum of the [Formula: see text] peak (IFWd2), the inverse of half-width at the half maximum of the [Formula: see text] peak (IHWd2), the phase plot slope, and the error ratio method. The IFWd2 and IHWd2 methods show the smallest variation among neurons of the same type. Furthermore, the AP rapidity, using the [Formula: see text] peak width methods, significantly differentiates between different types of neurons, indicating that AP rapidity can be used to classify neuron types. The AP rapidity measured using the IFWd2 method was able to differentiate between all four neuron types analyzed. Therefore, the [Formula: see text] peak width methods provide another sensitive tool to investigate the mechanisms impacting the AP onset dynamics.