• Каталог /
• Картинки /
• brewbooks /
• My mental...

Описание: Axons transmit information within the nervous system. Let me start with one of the central concepts of neuroscience, the neuron doctrine, first proposed by (Santiago Ram'on y Cajal ): discrete cells make up the nervous system. These cells are neurons; they are made up of dendrites, soma, and axons. In general, information flows from axons to dendrites. In my mental model of a neuron, dendrites are receivers or input devices, and it integrates excitatory or inhibitory inputs received from other neurons. I think of the dendrite inputs as analog signals; they continuously vary over time. The soma is a central processor that controls the form and function of the neuron. The axons are analog to digital converters and transmitters. The axon initial segment produces a digital action potential ("spike") when the summation of the voltages within the neuron are above a threshold. The action potential is a one-tenth of a volt electrical signal that travels down an axon at speeds up to about 100 meters per second. Myelin sheaths cover many axons; this increases the speed a signal can travel down an axon. The myelinated axons make up the white matter of the brain. Also, signals go faster when the axon diameter is larger. The function and form of axons varies, here are a few basic categories Figure 1.1, [Examples (A-F) of the rich...]. (www.ncbi.nlm.nih.gov/books/NBK10976/figure/A48/) References Khan Academy has many wonderful videos, here are three that will be very useful to understand the function of an axon 1. Neuron action potential description (www.khanacademy.org/science/health-and-medicine/nervous-s...) 2. Effects of axon diameter and myelination (www.khanacademy.org/science/health-and-medicine/nervous-s...) 3. Action potential patterns (www.khanacademy.org/science/health-and-medicine/nervous-s...) The textbook I used in Neuroscience class was: Purves, D., Augustine, G. J., Fitzpatrick, D., Hall, W. C., LaMantia, A.-S., & White, L. E. (2012). Neuroscience (5th ed.). Sunderland, Mass.: Sinauer Associates. There is a searchable version of the second edition of Neuroscience (www.ncbi.nlm.nih.gov/books/NBK10799/) My own model of neurons has been shaped by listening to a class by Idan Segev Synapses, Neurons and Brains (Coursera) Answer to a Quora question www.quora.com/What-is-the-function-of-axons-How-is-it-use... IMG_20160926_090044

Tags: