Neuroscience

Gaining insights into spastic paraplegia

Rare diseases, as the name indicates, only affect a small part of the population. However, for those affected they are particularly challenging, often especially because research into such rare diseases tends to be less of ...

Neuroscience

Atherosclerotic plaques 'talk' with the brain

A new study shows the existence of a connection between atherosclerotic plaques and the central nervous system. This previously unknown "circuit" involves three systemically acting tissues, the immune system, the nervous ...

Neuroscience

Transient BP spikes linked to learning area in the brain

Minor everyday rises in blood pressure due to short-term stressors can be linked to a brain area that controls conscious and learned motor skills. This discovery, presented by University of Gothenburg researchers, paves the ...

Neuroscience

How learning Braille changes brain structure over time

Learning changes the brain, but when learning Braille different brain regions strengthen their connections at varied rates and time frames. A new study published in JNeurosci highlights the dynamic nature of learning-induced ...

Medical research

How injured nerves stop themselves from healing

Three main causes for the inability of injured nerves of the central nervous system, or CNS, to regenerate have been known to date: the insufficient activation of a regeneration program in injured nerve cells that stimulates ...

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Axon

An axon or nerve fiber is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma.

An axon is one of two types of protoplasmic protrusions that extrude from the cell body of a neuron, the other type being dendrites. Axons are distinguished from dendrites by several features, including shape (dendrites often taper while axons usually maintain a constant radius), length (dendrites are restricted to a small region around the cell body while axons can be much longer), and function (dendrites usually receive signals while axons usually transmit them). All of these rules have exceptions, however.

Some types of neurons have no axon—these are called amacrine cells, and transmit signals from their dendrites. No neuron ever has more than one axon; however in invertebrates such as insects the axon sometimes consists of several regions that function more or less independently of each other. Most axons branch, in some cases very profusely.

Axons make contact with other cells—usually other neurons but sometimes muscle or gland cells—at junctions called synapses. At a synapse, the membrane of the axon closely adjoins the membrane of the target cell, and special molecular structures serve to transmit electrical or electrochemical signals across the gap. Some synaptic junctions appear partway along an axon as it extends—these are called en passant ("in passing") synapses. Other synapses appear as terminals at the ends of axonal branches. A single axon, with all its branches taken together, can innervate multiple parts of the brain and generate thousands of synaptic terminals.

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