Fine structure of synaptic contacts in the first order giant fibre system of the squid

AbstractSchistocerca gregaria possess four neurones of giant fibre proportions within the abdominal ventral nerve cord. These fibres arise from single cell bodies in the terminal ganglionic mass and pass without interruption to the metathoracic ganglion. Fibres become reduced in diameter when passing through a ganglion. Branching of the giant fibres occurs in abdominal ganglia 6 and 7.

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Neurofilament phosphorylation and axon diameter in the squid giant fibre system

Neuroscience ◽

10.1016/s0306-4522(98)00244-9 ◽

1999 ◽

Vol 88 (1) ◽

pp. 327-336 ◽

Cited By ~ 27

Author(s):

R Martin ◽

R Door ◽

A Ziegler ◽

W Warchol ◽

J Hahn ◽

...

Keyword(s):

Axon Diameter ◽

Giant Fibre ◽

Neurofilament Phosphorylation ◽

Giant Fibre System

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The Segmental Giant Neurone of the Hermit Crab Eupagurus Bernhardus

Journal of Experimental Biology ◽

10.1242/jeb.125.1.245 ◽

1986 ◽

Vol 125 (1) ◽

pp. 245-269 ◽

Cited By ~ 1

Author(s):

W. J. Heitler ◽

K. Fraser

Keyword(s):

Cell Body ◽

Hermit Crab ◽

Small Cell ◽

Electrical Synapse ◽

Giant Fibre ◽

Anatomy And Physiology ◽

Motor Neurones ◽

Evolutionary Paths ◽

Contralateral Motor ◽

Giant Fibre System

The anatomy and physiology of the segmental giant (SG) neurone of the fourth abdominal ganglion of the hermit crab is described. The SG has an apparently blindending axon in the first root and a small cell body in the anterior ipsilateral ventral quadrant of the ganglion. There is a large ipsilateral neuropile arborization with prominent dendrites lined up along the course of the ipsilateral giant fibre (GF). The SG receives 1:1 input from the ipsilateral GF via an electrical synapse which is usually rectifying. SG activation produces a large EPSP in all ipsilateral and some contralateral fast flexor excitor (FF) motor neurones. The major input to FFs resulting from GF activation appears to be mediated via the SG. It also produces a small EPSP in ipsilateral and contralateral motor giant neurones. The properties of the hermit crab SG are compared to those of the crayfish SG, and the implications of the SG for the possible evolutionary paths of the giant fibre system are discussed.

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The Myocardial Signature: Absolute Backscatter, Cyclical Variation, Frequency Variation, and Statistics

Ultrasonic Imaging ◽

10.1177/016173468600800203 ◽

1986 ◽

Vol 8 (2) ◽

pp. 107-120 ◽

Cited By ~ 23

Author(s):

T. L. Rhyne ◽

K. B. Sagar ◽

S. L. Wann ◽

G. Haasler

Keyword(s):

Fine Structure ◽

Cross Section ◽

Rayleigh Scattering ◽

Cardiac Cycle ◽

Frequency Variation ◽

Myocardial Ultrastructure ◽

Order Model ◽

Integrated Backscatter ◽

Cyclical Variation ◽

First Order

This paper studies the absolute myocardial backscatter as a function of the frequency and phase of the cardiac cycle. This was achieved by calibration of the ultrasonic instrumentation and the random diffraction process. We have discovered a first-order model in which the scattering from the myocardium is Rayleigh scattering with a cardiac cycle variation in the scattering cross section. Furthermore, the statistics are approximately those of a radio frequency waveform with two independent Gaussian components (Rayleigh envelope). Deviations from the first-order model suggest measurable fine structure related to myocardial ultrastructure. This model has profound effects on the choice of optimal radiation patterns and signal processing schemes for preparing diagnostic parameters (e.g., integrated backscatter).

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