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Neuropil, sometimes referred to as "neuropile," is a broad term defined as any area in the nervous system composed of mostly unmyelinated axons, dendrites and glial cell processes that forms a synaptically dense region containing a relatively low number of cell bodies. The most prevalent anatomical region of neuropil is the brain which, although not completely composed of neuropil, does have the largest and highest synaptically-concentrated areas of neuropil in the body. For example, the neocortex and olfactory bulb both contain neuropil. White matter, which is mostly composed of axons and glial cells, is generally not considered to be a part of the neuropil. thumb Neuropil (pl. neuropils) comes from the Greek: ''neuro'', meaning "tendon, sinew; nerve" and ''pilos'', meaning "felt."〔Freeman, Walter J. ''How Brains Make up their Minds '', 2000, p. 47〕 The term's origin can be traced back to the late 19th century. ==Examples== Neuropil has been found in the following regions: outer neocortex layer, barrel cortex, inner plexiform layer and outer plexiform layer, posterior pituitary, and glomeruli of the cerebellum. These are all found in humans, with the exception of the barrel cortex, but many species have counterparts similar to our own regions of neuropil. However, the degree of similarity depends upon the composition of neuropil being compared. The concentrations of neuropil within certain regions are important to determine because simply using the proportions of the different postsynaptic elements does not verify the necessary, conclusive evidence. Comparing the concentrations can determine whether or not proportions of different postsynaptic elements contacted a particular axonal pathway. Relative concentrations could signify a reflection of different postsynaptic elements in the neuropil or show that axons sought out and formed synapses only with specific postsynaptic elements. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「neuropil」の詳細全文を読む スポンサード リンク
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