Introduction
A neuron is composed of three main parts; the soma (cell body), the dendrites, and the axon. The soma contains the nucleus, the dendrites receive synaptic input (neurotransmitters), and the axon releases the neurotransmitters. The large branching structure of the dendrites and axon terminal allow each neuron to have connections to thousands of other neurons, forming a massive communication web.
A neuron communicates via action potentials. An action potential is an electric pulse that travels down the axon until it reaches the synapses, where it then causes the release of neurotransmitters. These action potentials are known as neuron firing or neuron spiking (1). Spiking neural networks (SNNs) fall into the third generation of neural network models, increasing the level of realism in a neural simulation. SNNs have become widely used in a variety of biological and engineering applications, and to date there have been a large number of neuron models that have been proposed in the scientific literature. The idea is that neurons in the SNN do not fire at each propagation cycle (as it happens with typical multi-layer perceptron networks), but rather fire only when an action potential reaches a specific value (2). This paper seeks to better understand the neuron models that are used in such endeavors, and to propose recommendations for which models should be used in certain circumstances and the computational costs of the different neuron models used to construct these spiking networks. It is important to simulate the behavior of individual neurons exactly. To these ends, this paper not only examines the cost of implementing different solution methods on different neuron models, but also studies how differe...
... middle of paper ...
...ks Cited
1) Hennessy M, Lewis G.M. Complex dynamics in a two-compartment neuronal model. http://faculty.uoit.ca/lewis/pubs/Hennessy_Neuron.pdf.
2) Skocik M.J., Long L.N. On the Capabilities and Computational Costs of Neuron Models. IEEE Transactions On Neural Networks and Learning Systems. 2013.
3) Hodgkin A.L. and Huxley, A.F. (1952) A quantitative description of membrane current and its application to conduction and excitation in nerve. J. Physiol. (Lond.) 117;500-544.
4) Izhikevich E.M. Simple model of spiking neurons. IEEE Trans. Neural Netw., vol. 14, no. 6, pp. 1569–1572, Nov. 2003.
5) Gerstner and Kistler. Spiking Neuron Models: Single Neurons, Populations, Plasticity. Cambridge University Press, 2002.
6) Riecke H. Modeling and Computation in Science and Engineering. 2013 http://people.esam.northwestern.edu/~riecke/Vorlesungen/346/Notes/notes.346.pdf.
The brain is an organ that regulates body functions, behaviors, and emotions. Neurons are the cells that fulfill these functions. How do neurons do this? A neuron plays an important role in the central nervous system. Why? Because neurons regulate how we think, feel, and control our body functions. A typical neuron has three parts: cell body, axon, and dendrites. When a neuron receives an electrical impulse, that impulse travels
Neurons dispatch signals to other cells through thin fibers called axons, that cause chemicals acknowledged as neurotransmitters to be released at junctions identified as synapses. A synapse gives a command to the cell and the entire communication process typically takes only a fraction of a millisecond.
The occurrence of action potential is a very short process. When action potential occurs in the neuron the sodium channels open along the axon and sodium comes in. Because the sodium is positive it make the inside of the axon positive. When both the inside and outside are comparative in charge the sodium storms rushing in and starts the depolarization of the action potential. After this happens the sodium channels begin to close and the potassium channels begin to ...
Kandel, E. R., J. H. Schwarz, and T. M. Jessel. Principles of Neural Science. 3rd ed. Elsevier. New York: 1991.
Dendrites are located on either one or both ends of a cell.The peripheral nervous system then takes the sensory information from the outside and sends the messages by virtue of neurotransmitters. Neurotransmitters are chemicals that relay signals through the neural pathways of the spinal cord. The neurotransmitter chemicals are held by tiny membranous sacs located in the synaptic terminals. Synaptic terminals are located at the ends of nerve cells. The release of neurotransmitters from their sacs is stimulated once the electrical nerve impulse has finished travelling along a neuron and reaches the synaptic terminal. Afterward, neurotransmitters travel across synapses thus stimulating the production of an electrical charge that carries the nerve impulse onward. Synapses are junctions between neighboring neurons. This procedure is reiterated until either muscle movement occurs or the brain picks up on a sensory reaction. During this process, messages are being transmitted from one part of the body onto the next. The peripheral and central nervous system are two crucial subdivisions of the nervous system. The brain and spinal cord make up the central nervous
The neurons or brain cells are shaped like trees. Young brain cells, called soma, resemble an acorn or small seed of a tree. The seed sprouts limbs when stimulated, called dendrites. Further on in development, the cell will grow a trunk like structure called an axon. The axon has an outer shell, like the bark of a tree, called the myelin sheath. Finally, at the base of the cell, there are root-like structures called axon terminal bulbs. Through these bulbs and the dendrite of another cell, cells communicate with each other through electrochemical impulses. These impulses cause the dendrites to
Schurger, A., Sitt, J. D., & Dehaene, S. (2012). An accumulator model for spontaneous neural activity prior to self-initiated movement. Proceedings of the National Academy of Sciences, 109(42), E2904-E2913. Retrieved March 21, 2014, from http://dx.doi.org/10.1073/pnas.1210467109
Stergiou, C., & Siganos, D. (2011, August 6). Neural Networks. Retrieved August 6, 2011, from
The introduction to the article was interesting, “What has billions of individual pieces, trillions of connections, weights about 1.4 kilograms, and works on electrochemical energy? If you guessed a minicomputer you’re wrong. If you guessed the human brain, you’re correct!” I did not know the brain had quite this many connections. After reading our chapter I really started to grasp the complexity of the human brain and the amount of energy it expends. I felt that the article lacked facts like these further in. There was very little empirical numbers offered by the author Eric Chudler.
Nerve cells generate electrical signals to transmit information. Neurons are not necessarily intrinsically great electrical conductors, however, they have evolved specialized mechanisms for propagating signals based on the flow of ions across their membranes.
The neuron plays an important role in the occupation of the brain (Rollin Koscis). A neuron is...
Sperry, R. W. (1963, October 15). Chemoaffinity in the Orderly Growth of Nerve Fiber Patterns and Connection. Natioanl Academy of Science, 50(4), 703-710.
Synaptic transmission is the process of the communication of neurons. Communication between neurons and communication between neuron and muscle occurs at specialized junction called synapses. The most common type of synapse is the chemical synapse. Synaptic transmission begins when the nerve impulse or action potential reaches the presynaptic axon terminal. The action potential causes depolarization of the presynaptic membrane and it will initiates the sequence of events leading to release the neurotransmitter and then, the neurotransmitter attach to the receptor at the postsynaptic membrane and it will lead to the activate of the postsynaptic membrane and continue to send the impulse to other neuron or sending the signal to the muscle for contraction (Breedlove, Watson, & Rosenzweig, 2012; Barnes, 2013). Synaptic vesicles exist in different type, either tethered to the cytoskeleton in a reserve pool, or free in the cytoplasm (Purves, et al., 2001). Some of the free vesicles make their way to the plasma membrane and dock, as a series of priming reactions prepares the vesicular ...
The brain consists of both neurons and glia cells. The neurons, which are cells housed in a cell body called a Soma, have branches which extend from them, referred to as dendrites. From these dendrites extend axons which send and receive impulses, ending at junction points called synapses. It is at these synapse points that the transfer of information takes place.
[online] Available at: http://www.livescience.com/22665-nervous system.html [Accessed: 1 Oct 2013]. Reece, J. 2012. The. Campbell biology. San Francisco, CA. -.