A neuron, neurone, or nerve cell is an excitable cell that fires electric signals called action potentials across a neural network in the nervous system. They are located in the brain and spinal cord and help to receive and conduct impulses. Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap.
Computational neuroscience is a branch of neuroscience which employs mathematics, computer science, theoretical analysis and abstractions of the brain to understand the principles that govern the development, structure, physiology and cognitive abilities of the nervous system.
An electrical synapse, or gap junction, is a mechanical and electrically conductive synapse, a functional junction between two neighboring neurons. The synapse is formed at a narrow gap between the pre- and postsynaptic neurons known as a gap junction. At gap junctions, such cells approach within about 3.8 nm of each other, a much shorter distance than the 20- to 40-nanometer distance that separates cells at a chemical synapse. In many animals, electrical synapse-based systems co-exist with chemical synapses.
A neural circuit is a population of neurons interconnected by synapses to carry out a specific function when activated. Multiple neural circuits interconnect with one another to form large scale brain networks.
Neuronal noise or neural noise refers to the random intrinsic electrical fluctuations within neuronal networks. These fluctuations are not associated with encoding a response to internal or external stimuli and can be from one to two orders of magnitude. Most noise commonly occurs below a voltage-threshold that is needed for an action potential to occur, but sometimes it can be present in the form of an action potential; for example, stochastic oscillations in pacemaker neurons in suprachiasmatic nucleus are partially responsible for the organization of circadian rhythms.
In the nervous system, a synapse is a structure that allows a neuron to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending on the mechanism of signal transmission between neurons. In the case of electrical synapses, neurons are coupled bidirectionally with each other through gap junctions and have a connected cytoplasmic milieu. These types of synapses are known to produce synchronous network activity in the brain, but can also result in complicated, chaotic network level dynamics. Therefore, signal directionality cannot always be defined across electrical synapses.
In neuroscience, homeostatic plasticity refers to the capacity of neurons to regulate their own excitability relative to network activity. The term homeostatic plasticity derives from two opposing concepts: 'homeostatic' and plasticity, thus homeostatic plasticity means "staying the same through change". In the nervous system, neurons must be able to evolve with the development of their constantly changing environment while simultaneously staying the same amidst this change. This stability is important for neurons to maintain their activity and functionality to prevent neurons from carcinogenesis. At the same time, neurons need to have flexibility to adapt to changes and make connections to cope with the ever-changing environment of a developing nervous system.
The development of the nervous system in humans, or neural development, or neurodevelopment involves the studies of embryology, developmental biology, and neuroscience. These describe the cellular and molecular mechanisms by which the complex nervous system forms in humans, develops during prenatal development, and continues to develop postnatally.
Connectomics is the production and study of connectomes: comprehensive maps of connections within an organism's nervous system. More generally, it can be thought of as the study of neuronal wiring diagrams with a focus on how structural connectivity, individual synapses, cellular morphology, and cellular ultrastructure contribute to the make up of a network. The nervous system is a network made of up to billions of connections and these connections are responsible for our thoughts, emotions, actions, memories, function and dysfunction. Therefore, the study of connectomics aims to advance our understanding of mental health and cognition by understanding how cells in the nervous system are connected and communicate. Because these structures are extremely complex, methods within this field use a high-throughput application of functional and structural neural imaging, most commonly magnetic resonance imaging (MRI), electron microscopy, and histological techniques in order to increase the speed, efficiency, and resolution of these nervous system maps. To date, tens of large scale datasets have been collected spanning the nervous system including the various areas of cortex, cerebellum, the retina, the peripheral nervous system and neuromuscular junctions.
In the field of computational neuroscience, brain simulation is the concept of creating a functioning computer model of a brain or part of a brain. Brain simulation projects intend to contribute to a complete understanding of the brain, and eventually also assist the process of treating and diagnosing brain diseases. Simulations utilize mathematical models of biological neurons, such as the hodgkin-huxley model, to simulate the behavior of neurons, or other cells within the brain.
Developmental plasticity is a general term referring to changes in neural connections during development as a result of environmental interactions as well as neural changes induced by learning. Much like neuroplasticity, or brain plasticity, developmental plasticity is specific to the change in neurons and synaptic connections as a consequence of developmental processes. A child creates most of these connections from birth to early childhood. There are three primary methods by which this may occur as the brain develops, but critical periods determine when lasting changes may form. Developmental plasticity may also be used in place of the term phenotypic plasticity when an organism in an embryonic or larval stage can alter its phenotype based on environmental factors. However, a main difference between the two is that phenotypic plasticity experienced during adulthood can be reversible, whereas traits that are considered developmentally plastic set foundations during early development that remain throughout the life of the organism.
Retrograde tracing is a research method used in neuroscience to trace neural connections from their point of termination to their source. Retrograde tracing techniques allow for detailed assessment of neuronal connections between a target population of neurons and their inputs throughout the nervous system. These techniques allow the "mapping" of connections between neurons in a particular structure and the target neurons in the brain. The opposite technique is anterograde tracing, which is used to trace neural connections from their source to their point of termination. Both the anterograde and retrograde tracing techniques are based on the visualization of axonal transport.
NeuroML is an XML based model description language that aims to provide a common data format for defining and exchanging models in computational neuroscience. The focus of NeuroML is on models which are based on the biophysical and anatomical properties of real neurons.
An autapse is a chemical or electrical synapse from a neuron onto itself. It can also be described as a synapse formed by the axon of a neuron on its own dendrites, in vivo or in vitro.
Michael A. Häusser is a British scientist who is professor of Neuroscience, based in the Wolfson Institute for Biomedical Research at University College London (UCL).
Dimitri Michael Kullmann is a British neurologist who is a professor of neurology at the UCL Institute of Neurology, University College London (UCL), and leads the synaptopathies initiative funded by the Wellcome Trust. Kullmann is a member of the Queen Square Institute of Neurology Department of Clinical and Experimental Epilepsy and a consultant neurologist at the National Hospital for Neurology and Neurosurgery.
Neil Burgess is a British neuroscientist. He has been a professor of cognitive neuroscience at University College London since 2004 and a Wellcome Trust Principal Research Fellow since 2011. He has made important contributions to understanding memory and spatial cognition by developing computational models relating behaviour to activity in biological neural networks.
Tara Keck is an American-British neuroscientist and Professor of Neuroscience and Wellcome Trust Senior Research Fellow, at University College London working in the Department of Neuroscience, Physiology, and Pharmacology. She is the Vice-Dean International for the Faculty of Life Sciences. She studies experience-dependent synaptic plasticity, its effect on behaviour and how it changes during ageing and age-related diseases. She has worked in collaboration with the United Nations Population Fund on approaches for healthy ageing. Her recent work has focused on loneliness in older people, with a focus on gender. She was named a UNFPA Generations and Gender Fellow in 2022.
Tom Mrsic-Flogel is an experimental neuroscientist. He is Director of the Sainsbury Wellcome Centre and a Professor in Neuroscience at University College London (UCL). Mrsic-Flogel is a founding member of the International Brain Laboratory.
Annalisa Scimemi is a neuroscientist on the faculty of the State University of New York at Albany (SUNY).
