Synaptic contacts between physiologically identified neurons in the visual system of the barnacle

Bruce Schnapp, A. E. Stuart

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Neurons in the median visual system of the barnacle were injected with horseradish peroxidase (HRP) and their processes traced in serial thick (3μ) and thin (100 nm) sections with light and electron microscopy. The anatomy confirms that the I-cells identified by Oertel and Stuart are second-order neurons in the median visual pathway. The terminal branches of the photoreceptor axons are associated in each half of the supraesophageal ganglion with a region of neuropil that extends for 30 to 40 μm along the commissure; this photoreceptor-associated neuropil is continuous with but much simpler than the main mass of neuropil in the core of each hemiganglion. The photoreceptor-associated neuropil consists of a small number of different neuronal elements, each with distinctive cytological features. The photoreceptor terminal processes dominate the neuropil; in addition, one finds there the most medial processes of the arborizations of the ipsilateral and contralateral I-cells and the processes of an axon or class of axons of unknown origin referred to as the 'RL' fibers. These RL processes associate and branch with the receptor axons and constitute the only major neuronal element in this region of neuropil besides the median photoreceptors and the I-cells. In preparations with an HRP-filled I-cell, the photoreceptors were shown to be presynaptic to I-cell processes at synapses which are characterized by a pair of closely apposed postsynaptic profiles referred to as a dyad. The filled I-cell constituted only one element of the dyad. Receptor endings were also presynaptic to dyads where both postsynaptic elements were unfilled. The RL processes were presynaptic to the photoreceptor terminals at nondyadic synapses, and the receptor endings made specialized junctions, possibly synaptic, with the RL processes. Lateral to the region occupied by the photoreceptor arborization, varicosities of the I-cell are juxtaposed to processes of the A-cell; thus, these sites of the I-cell, where it is most likely to be presynaptic to the A-cell, are segregated from the sites at which it is postsynaptic to the photoreceptors. The I-cell is postsynaptic to photoreceptors and has varicosities juxtaposed to A-cell processes in both hemiganglia.

Original languageEnglish (US)
Pages (from-to)1100-1115
Number of pages16
JournalJournal of Neuroscience
Volume3
Issue number5
StatePublished - 1983
Externally publishedYes

Fingerprint

Thoracica
Neuropil
Neurons
Axons
Photoreceptor Cells
Horseradish Peroxidase
Synapses
Visual Pathways
Ganglia
Anatomy
Electron Microscopy

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Synaptic contacts between physiologically identified neurons in the visual system of the barnacle. / Schnapp, Bruce; Stuart, A. E.

In: Journal of Neuroscience, Vol. 3, No. 5, 1983, p. 1100-1115.

Research output: Contribution to journalArticle

@article{3607043a4d5a4d39ba30b47312840b0a,
title = "Synaptic contacts between physiologically identified neurons in the visual system of the barnacle",
abstract = "Neurons in the median visual system of the barnacle were injected with horseradish peroxidase (HRP) and their processes traced in serial thick (3μ) and thin (100 nm) sections with light and electron microscopy. The anatomy confirms that the I-cells identified by Oertel and Stuart are second-order neurons in the median visual pathway. The terminal branches of the photoreceptor axons are associated in each half of the supraesophageal ganglion with a region of neuropil that extends for 30 to 40 μm along the commissure; this photoreceptor-associated neuropil is continuous with but much simpler than the main mass of neuropil in the core of each hemiganglion. The photoreceptor-associated neuropil consists of a small number of different neuronal elements, each with distinctive cytological features. The photoreceptor terminal processes dominate the neuropil; in addition, one finds there the most medial processes of the arborizations of the ipsilateral and contralateral I-cells and the processes of an axon or class of axons of unknown origin referred to as the 'RL' fibers. These RL processes associate and branch with the receptor axons and constitute the only major neuronal element in this region of neuropil besides the median photoreceptors and the I-cells. In preparations with an HRP-filled I-cell, the photoreceptors were shown to be presynaptic to I-cell processes at synapses which are characterized by a pair of closely apposed postsynaptic profiles referred to as a dyad. The filled I-cell constituted only one element of the dyad. Receptor endings were also presynaptic to dyads where both postsynaptic elements were unfilled. The RL processes were presynaptic to the photoreceptor terminals at nondyadic synapses, and the receptor endings made specialized junctions, possibly synaptic, with the RL processes. Lateral to the region occupied by the photoreceptor arborization, varicosities of the I-cell are juxtaposed to processes of the A-cell; thus, these sites of the I-cell, where it is most likely to be presynaptic to the A-cell, are segregated from the sites at which it is postsynaptic to the photoreceptors. The I-cell is postsynaptic to photoreceptors and has varicosities juxtaposed to A-cell processes in both hemiganglia.",
author = "Bruce Schnapp and Stuart, {A. E.}",
year = "1983",
language = "English (US)",
volume = "3",
pages = "1100--1115",
journal = "Journal of Neuroscience",
issn = "0270-6474",
publisher = "Society for Neuroscience",
number = "5",

}

TY - JOUR

T1 - Synaptic contacts between physiologically identified neurons in the visual system of the barnacle

AU - Schnapp, Bruce

AU - Stuart, A. E.

PY - 1983

Y1 - 1983

N2 - Neurons in the median visual system of the barnacle were injected with horseradish peroxidase (HRP) and their processes traced in serial thick (3μ) and thin (100 nm) sections with light and electron microscopy. The anatomy confirms that the I-cells identified by Oertel and Stuart are second-order neurons in the median visual pathway. The terminal branches of the photoreceptor axons are associated in each half of the supraesophageal ganglion with a region of neuropil that extends for 30 to 40 μm along the commissure; this photoreceptor-associated neuropil is continuous with but much simpler than the main mass of neuropil in the core of each hemiganglion. The photoreceptor-associated neuropil consists of a small number of different neuronal elements, each with distinctive cytological features. The photoreceptor terminal processes dominate the neuropil; in addition, one finds there the most medial processes of the arborizations of the ipsilateral and contralateral I-cells and the processes of an axon or class of axons of unknown origin referred to as the 'RL' fibers. These RL processes associate and branch with the receptor axons and constitute the only major neuronal element in this region of neuropil besides the median photoreceptors and the I-cells. In preparations with an HRP-filled I-cell, the photoreceptors were shown to be presynaptic to I-cell processes at synapses which are characterized by a pair of closely apposed postsynaptic profiles referred to as a dyad. The filled I-cell constituted only one element of the dyad. Receptor endings were also presynaptic to dyads where both postsynaptic elements were unfilled. The RL processes were presynaptic to the photoreceptor terminals at nondyadic synapses, and the receptor endings made specialized junctions, possibly synaptic, with the RL processes. Lateral to the region occupied by the photoreceptor arborization, varicosities of the I-cell are juxtaposed to processes of the A-cell; thus, these sites of the I-cell, where it is most likely to be presynaptic to the A-cell, are segregated from the sites at which it is postsynaptic to the photoreceptors. The I-cell is postsynaptic to photoreceptors and has varicosities juxtaposed to A-cell processes in both hemiganglia.

AB - Neurons in the median visual system of the barnacle were injected with horseradish peroxidase (HRP) and their processes traced in serial thick (3μ) and thin (100 nm) sections with light and electron microscopy. The anatomy confirms that the I-cells identified by Oertel and Stuart are second-order neurons in the median visual pathway. The terminal branches of the photoreceptor axons are associated in each half of the supraesophageal ganglion with a region of neuropil that extends for 30 to 40 μm along the commissure; this photoreceptor-associated neuropil is continuous with but much simpler than the main mass of neuropil in the core of each hemiganglion. The photoreceptor-associated neuropil consists of a small number of different neuronal elements, each with distinctive cytological features. The photoreceptor terminal processes dominate the neuropil; in addition, one finds there the most medial processes of the arborizations of the ipsilateral and contralateral I-cells and the processes of an axon or class of axons of unknown origin referred to as the 'RL' fibers. These RL processes associate and branch with the receptor axons and constitute the only major neuronal element in this region of neuropil besides the median photoreceptors and the I-cells. In preparations with an HRP-filled I-cell, the photoreceptors were shown to be presynaptic to I-cell processes at synapses which are characterized by a pair of closely apposed postsynaptic profiles referred to as a dyad. The filled I-cell constituted only one element of the dyad. Receptor endings were also presynaptic to dyads where both postsynaptic elements were unfilled. The RL processes were presynaptic to the photoreceptor terminals at nondyadic synapses, and the receptor endings made specialized junctions, possibly synaptic, with the RL processes. Lateral to the region occupied by the photoreceptor arborization, varicosities of the I-cell are juxtaposed to processes of the A-cell; thus, these sites of the I-cell, where it is most likely to be presynaptic to the A-cell, are segregated from the sites at which it is postsynaptic to the photoreceptors. The I-cell is postsynaptic to photoreceptors and has varicosities juxtaposed to A-cell processes in both hemiganglia.

UR - http://www.scopus.com/inward/record.url?scp=0020540348&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0020540348&partnerID=8YFLogxK

M3 - Article

VL - 3

SP - 1100

EP - 1115

JO - Journal of Neuroscience

JF - Journal of Neuroscience

SN - 0270-6474

IS - 5

ER -