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A fibril of a neuron, usually extending from the processes and traversing the cell body.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a microscopic filament that is found upon treatment of nerve cells—neurons—and the longest outgrowths of the nerve cells—axons—with silver salts and other reagents.

In the late 19th and early 20th centuries, neurofibrils were ascribed the function of conducting nerve impulses. This view proved to be erroneous when it was found that nerve impulses are conducted by the external membrane of the neuron. Electron microscopy revealed two kinds of longitudinal neurofibrils in the outgrowths of neurons: neurotubules and neurofilaments. Neurotubules are from 20 to 25 nm in diameter and are formed from the protein tubulin; they are believed to transport substances along the axon. The threadlike neurofilaments are formed from a protein similar to the muscle protein actin. Neurofilaments are especially numerous in the movable terminal portions of growing axons.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Finally, it appears that once A[Beta] is deposited in the neuropil, it triggers a cascade of events that include microglial activation, neuritic abnormalities, and neurofibrillary tangles.
NEUROFIBRILLARY TANGLE--an accumulation of abnormal fibers in the nerve cells in the cerebral cortex.
"Together, the sex difference in the association between APOE and CSF measures of tau and the lack of a sex difference in the association with neurofibrillary tangles at autopsy suggest that APOE may modulate risk for neurodegeneration in a sex-specific manner, particularly in the presence of amyloidosis," the authors write.
Amyloid plaques and neurofibrillary tangles in the brain are the principal hallmarks of AD, and their formation is associated with the degradation of neurons (nerve cells) in the brain, leading to symptoms of the disease.
Neurofibrillary tangles, which are composed of abnormally phosphorylated tau protein aggregates, appear as parallel, thickened fibrils that extend toward the apical dendrite of pyramidal neurons.
The final study examined the effect of an active tau immunotherapy on mice engineered to develop neurofibrillary tau tangles.
One particular group of heterogeneous dementias and movement disorders is characterized by intracellular accumulations of abnormal filaments called neurofibrillary tangles (NFT), formed by the microtubule-associated protein tau.
Today, he says, it's most likely that there are two primary causes of dementia: an Alzheimer's disease type "pathology," represented by the neurofibrillary tangles and senile plaques of the disease, and vascular dementia, resulting from significant changes in blood vessels in the brain.
It cleared out that protein and another one that makes up the cell-killing "neurofibrillary tangles".
The brains of AD patients have clumps of fibrous proteins called neurofibrillary
Brain tissue samples of Alzheimer's victims reveal extensive neuronal cell death, as well as two abnormal pathological structures known as "neurofibrillary tangles" and "amyloid plaques."
From pathologic reviews, hallmarks of AD include extracellular plaques and intracellular neurofibrillary tangles in parts of the brain involved with cognition and memory.