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Nervous tissue consisting of a fibrous network of nonmyelinated nerve fibers; gray matter with few nerve cell bodies; usually a region of synapses between axons and dendrites.



(1) An obsolete term designating a fibrous nerve tissue structure that is found predominantly in invertebrates. The supposedly interconnected nerve fibers form a continuous cytoplasmic network that resembles a syncytium. This use of the term “neuropil” does not accurately reflect the microstructure of the nervous system. (See.)

(2) The fibrous nerve tissue structure in which synaptic contacts between neuronal outgrowths are concentrated.

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Principal and secondary visual inputs are processed in separate pathways with distinct neuropil regions, including separate laminae and medullae (Strausfeld and Barth, 1993; Strausfeld et al.
The ir nerve fibers were detected throughout the neuropils of the ganglion, especially in the dorsal and ventral horns (Fig.
In branchiopods, there are always only two visual neuropils and they are not linked by crossing fibers.
In these animals, such chemosensory information is conveyed to the central nervous system through two anatomically distinct but parallel pathways: the aesthetascolfactory lobe pathway and the non-aesthetasc-lateral antennular neuropil pathway, which are reciprocally connected by local olfactory interneurons (Schmidt et al.
The immunoreactivity of both types of nerve fibers were also found throughout the neuropils of the ganglia, especially in the dorsal and ventral horn regions, (Fig.
A second possible supportive structure found in this study consisted of ubiquitous fibrous bodies in the neuropils and axonal bundles.
Antennular withdrawal motoneurons in the lateral antennular neuropil of Callinectes sapidus.
The dorsal lobe is located in the dorsal region of the anterior and posterior lobes, which are characterized by small neuropils (asterisks in Fig.
In contrast, no cellular elements displaying GLU-L immunoreactivity could be found during embryogenesis, apart from a few sensory elements localized in the tail and a strong but partly undifferentiated immunoreactivity in the ganglion neuropils.
This region of glomerular neuropil has proved to be enigmatic in both its functional significance and its capricious appearance across taxa (Sandeman and Sandeman, 1994; Sandeman et al.
By day 4, the various 5-HT-containing fibers became more intensely stained as they projected into the neuropil and velum, with the elaboration of velar and apical innervation continuing through days 5 and 6 (Fig.
In the CG, as in crustacean ganglia generally, synaptic interactions occur in complex neuropils formed by collateral processes and branches from axons (Alexandrowicz, 1932, 1934, 1952; Obsawn, 1972; Aizu, 1975; Hawkins and Howse, 1978; Mirolli et at.