In physiology, an action potential (AP) occurs when the membrane potential of a specific cell location rapidly rises and falls: this depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, endocrine cells and in some plant cells.
BK channels (big potassium), are large conductance calcium-activated potassium channels, also known as Maxi-K, slo1, or Kca1.1. BK channels are voltage-gated potassium channels that conduct large amounts of potassium ions (K+) across the cell membrane, hence their name, big potassium. These channels can be activated (opened) by either electrical means, or by increasing Ca2+ concentrations in the cell. BK channels help regulate physiological processes, such as circadian behavioral rhythms and neuronal excitability. BK channels are also involved in many processes in the body, as it is a ubiquitous channel. They have a tetrameric structure that is composed of a transmembrane domain, voltage sensing domain, potassium channel domain, and a cytoplasmic C-terminal domain, with many X-ray structures for reference. Their function is to repolarize the membrane potential by allowing for potassium to flow outward, in response to a depolarization or increase in calcium levels.
An inhibitory postsynaptic potential (IPSP) is a kind of synaptic potential that makes a postsynaptic neuron less likely to generate an action potential. IPSP were first investigated in motorneurons by David P. C. Lloyd, John Eccles and Rodolfo Llinás in the 1950s and 1960s. The opposite of an inhibitory postsynaptic potential is an excitatory postsynaptic potential (EPSP), which is a synaptic potential that makes a postsynaptic neuron more likely to generate an action potential. IPSPs can take place at all chemical synapses, which use the secretion of neurotransmitters to create cell to cell signalling. Inhibitory presynaptic neurons release neurotransmitters that then bind to the postsynaptic receptors; this induces a change in the permeability of the postsynaptic neuronal membrane to particular ions. An electric current that changes the postsynaptic membrane potential to create a more negative postsynaptic potential is generated, i.e. the postsynaptic membrane potential becomes more negative than the resting membrane potential, and this is called hyperpolarisation. To generate an action potential, the postsynaptic membrane must depolarize—the membrane potential must reach a voltage threshold more positive than the resting membrane potential. Therefore, hyperpolarisation of the postsynaptic membrane makes it less likely for depolarisation to sufficiently occur to generate an action potential in the postsynaptic neurone.
Rodolfo Llinás Riascos is a Colombian-born American neuroscientist. He is currently the Thomas and Suzanne Murphy Professor of Neuroscience and Chairman Emeritus of the Department of Physiology & Neuroscience at the NYU School of Medicine. Llinás has published over 800 scientific articles.
The Even language, also known as Lamut, Ewen, Eben, Orich, Ilqan, is a Tungusic language spoken by the Evens in Siberia. It is spoken by widely scattered communities of reindeer herders from Kamchatka and the Sea of Okhotsk in the east to the Lena river in the west and from the Arctic coast in the north to the Aldan river in the south. Even is an endangered language with only some 5,700 speakers. These speakers are specifically from the Magadan region, the Chukot region and the Koryak region. The dialects are Arman, Indigirka, Kamchatka, Kolyma-Omolon, Okhotsk, Ola, Tompon, Upper Kolyma, Sakkyryr and Lamunkhin.
Bursting, or burst firing, is an extremely diverse general phenomenon of the activation patterns of neurons in the central nervous system and spinal cord where periods of rapid action potential spiking are followed by quiescent periods much longer than typical inter-spike intervals. Bursting is thought to be important in the operation of robust central pattern generators, the transmission of neural codes, and some neuropathologies such as epilepsy. The study of bursting both directly and in how it takes part in other neural phenomena has been very popular since the beginnings of cellular neuroscience and is closely tied to the fields of neural synchronization, neural coding, plasticity, and attention.
T-type calcium channels are low voltage activated calcium channels that become inactivated during cell membrane hyperpolarization but then open to depolarization. The entry of calcium into various cells has many different physiological responses associated with it. Within cardiac muscle cell and smooth muscle cells voltage-gated calcium channel activation initiates contraction directly by allowing the cytosolic concentration to increase. Not only are T-type calcium channels known to be present within cardiac and smooth muscle, but they also are present in many neuronal cells within the central nervous system. Different experimental studies within the 1970s allowed for the distinction of T-type calcium channels from the already well-known L-type calcium channels. The new T-type channels were much different from the L-type calcium channels due to their ability to be activated by more negative membrane potentials, had small single channel conductance, and also were unresponsive to calcium antagonist drugs that were present. These distinct calcium channels are generally located within the brain, peripheral nervous system, heart, smooth muscle, bone, and endocrine system.
The R-type calcium channel is a type of voltage-dependent calcium channel. Like the others of this class, the α1 subunit forms the pore through which calcium enters the cell and determines most of the channel's properties. This α1 subunit is also known as the calcium channel, voltage-dependent, R type, alpha 1E subunit (CACNA1E) or Cav2.3 which in humans is encoded by the CACNA1E gene. They are strongly expressed in cortex, hippocampus, striatum, amygdala and interpeduncular nucleus.
Low-threshold spikes (LTS) refer to membrane depolarizations by the T-type calcium channel. LTS occur at low, negative, membrane depolarizations. They often follow a membrane hyperpolarization, which can be the result of decreased excitability or increased inhibition. LTS result in the neuron reaching the threshold for an action potential. LTS is a large depolarization due to an increase in Ca2+ conductance, so LTS is mediated by calcium (Ca2+) conductance. The spike is typically crowned by a burst of two to seven action potentials, which is known as a low-threshold burst. LTS are voltage dependent and are inactivated if the cell's resting membrane potential is more depolarized than −60mV. LTS are deinactivated, or recover from inactivation, if the cell is hyperpolarized and can be activated by depolarizing inputs, such as excitatory postsynaptic potentials (EPSP). LTS were discovered by Rodolfo Llinás and coworkers in the 1980s.
Hyperpolarization-activated cyclic nucleotide–gated (HCN) channels are integral membrane proteins that serve as nonselective voltage-gated cation channels in the plasma membranes of heart and brain cells. HCN channels are sometimes referred to as pacemaker channels because they help to generate rhythmic activity within groups of heart and brain cells. HCN channels are activated by membrane hyperpolarization, are permeable to Na+ and K+, and are constitutively open at voltages near the resting membrane potential. HCN channels are encoded by four genes and are widely expressed throughout the heart and the central nervous system.
In neurophysiology, a dendritic spike refers to an action potential generated in the dendrite of a neuron. Dendrites are branched extensions of a neuron. They receive electrical signals emitted from projecting neurons and transfer these signals to the cell body, or soma. Dendritic signaling has traditionally been viewed as a passive mode of electrical signaling. Unlike its axon counterpart which can generate signals through action potentials, dendrites were believed to only have the ability to propagate electrical signals by physical means: changes in conductance, length, cross sectional area, etc. However, the existence of dendritic spikes was proposed and demonstrated by W. Alden Spencer, Eric Kandel, Rodolfo Llinás and coworkers in the 1960s and a large body of evidence now makes it clear that dendrites are active neuronal structures. Dendrites contain voltage-gated ion channels giving them the ability to generate action potentials. Dendritic spikes have been recorded in numerous types of neurons in the brain and are thought to have great implications in neuronal communication, memory, and learning. They are one of the major factors in long-term potentiation.
Oleksandr Prokopovych Markevych, in English more often Aleksandr Prokofyevich Markevich was a Ukrainian zoologist, and a prolific helminthologist and copepodologist. He was professor and an Academician of the National Academy of Sciences of Ukraine.
Boris Khodorov was a Soviet and Russian physiologist, M.D., D.Sc., Professor of Physiology, and Head of the Cell Physiology section of Moscow Physiological Society.
Platon Hryhorovych Kostyuk was a Ukrainian physiologist, neurobiologist, electrophysiologist, and biophysicist. He was a member (academician) of the National Academy of Sciences (NAS) of Ukraine and the Russian Academy of Sciences. He was also a director of the Bogomoletz Institute of Physiology and the International Center of Molecular Physiology NAS of Ukraine; chair of the Moscow Institute of Physics and Technology, Kyiv branch, vice-president of the NAS of Ukraine, and chairman of the Verkhovna Rada of the Ukrainian SSR.
Annette Catherine Dolphin is a Professor of Pharmacology in the Department of Neuroscience, Physiology and Pharmacology at University College London (UCL).
Rishikesh Narayanan is an Indian neuroscientist, computer engineer and a professor at the Molecular Biophysics Unit (MBU) of the Indian Institute of Science. He is the principal investigator at the Cellular Neurophysiology Laboratory of MBU where his team is engaged in researches on experimental and theoretical aspects of information processing in single neurons and their networks. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards, in 2016, for his contributions to biological sciences.
Vladimir Isaakovich Minkin is a Russian chemist. Professor, Doctor of Chemical Sciences.
Diane Lipscombe, Ph.D. is a professor of neuroscience and the Reliance Dhirubhai Ambani Director of Brown University’s Robert J. and Nancy D. Carney Institute for Brain Science. She served as the president of the Society for Neuroscience in 2019, the world’s largest organization for the study of the brain and nervous system.
Alexei Verkhratsky, sometimes spelled Alexej, is a professor of neurophysiology at the University of Manchester best known for his research on the physiology and pathophysiology of neuroglia, calcium signalling, and brain ageing. He is an elected member and vice-president of Academia Europaea, of the German National Academy of Sciences Leopoldina, of the Real Academia Nacional de Farmacia (Spain), of the Slovenian Academy of Sciences and Arts, of Polish Academy of Sciences, and Dana Alliance for Brain Initiatives, among others. Since 2010. he is a Ikerbasque Research Professor and from 2012 he is deputy director of the Achucarro Basque Center for Neuroscience in Bilbao. He is a distinguished professor at Jinan University, China Medical University of Shenynag, and Chengdu University of Traditional Chinese Medicine and is an editor-in-chief of Cell Calcium, receiving editor for Cell Death and Disease, and Acta Physiologica and member of editorial board of many academic journals.
Galyna Grygorivna Skibo - Ukrainian scientist, doctor of medical sciences, professor, corresponding member of the National Academy of Sciences of Ukraine (2018), laureate of the awards of the National Academy of Sciences of Ukraine named after O.O. Bogomolets (1996) and P.G. Kostiuk (2019), winner of the State Prize of Ukraine in the field of science and technology (2013), Honored Worker of Science and Technology of Ukraine (2006), head of the Cytology department of the Bogomoletz Institute of Physiology NAS of Ukraine, professor of NSC "Institute of Biology and Medicine" of Taras Shevchenko National University of Kyiv.
