scholarly journals Wnt/PCP proteins regulate stereotyped axon branch extension in Drosophila

Development ◽  
2011 ◽  
Vol 139 (1) ◽  
pp. 165-177 ◽  
Author(s):  
J. Ng
Keyword(s):  
Axon Branch

Action of a diffusible target-derived chemoattractant on cortical axon branch induction and directed growth

Neuron ◽  
1994 ◽  
Vol 13 (4) ◽  
pp. 791-803 ◽  
Author(s):  
Makoto Sato ◽  
Laura Lopez-Mascaraque ◽  
Christopher D. Heffnerai ◽  
Dennis D.M. O'Leary
Keyword(s):  
Directed Growth ◽  
Axon Branch

scholarly journals Action Potential Reflection and Failure at Axon Branch Points Cause Stepwise Changes in EPSPs in a Neuron Essential for Learning

2000 ◽  
Vol 83 (3) ◽  
pp. 1693-1700 ◽  
Author(s):  
Stephen A. Baccus ◽  
Brian D. Burrell ◽  
Christie L. Sahley ◽  
Kenneth J. Muller
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Conduction Block ◽  
Neuronal Morphology ◽  
Whole Body ◽  
Reverse Direction ◽  
Mammalian Brain ◽  
Branch Points ◽  
Individual Branch ◽  
Axon Branch

In leech mechanosensory neurons, action potentials reverse direction, or reflect, at central branch points. This process enhances synaptic transmission from individual axon branches by rapidly activating synapses twice, thereby producing facilitation. At the same branch points action potentials may fail to propagate, which can reduce transmission. It is now shown that presynaptic action potential reflection and failure under physiological conditions influence transmission to the same postsynaptic neuron, the S cell. The S cell is an interneuron essential for a form of nonassociative learning, sensitization of the whole body shortening reflex. The P to S synapse has components that appear monosynaptic (termed “direct”) and polysynaptic, both with glutamatergic pharmacology. Reflection at P cell branch points on average doubled transmission to the S cell, whereas action potential failure, or conduction block, at the same branch points decreased it by one-half. Each of two different branch points affected transmission, indicating that the P to S connection is spatially distributed around these branch points. This was confirmed by examining the locations of individual contacts made by the P cell with the S cell and its electrically coupled partner C cells. These results show that presynaptic neuronal morphology produces a range of transmission states at a set of synapses onto a neuron necessary for a form of learning. Reflection and conduction block are activity-dependent and are basic properties of action potential propagation that have been seen in other systems, including axons and dendrites in the mammalian brain. Individual branch points and the distribution of synapses around those branch points can substantially influence neuronal transmission and plasticity.

Multiple Sites of Spike Initiation in a Bifurcating Locust Neurone

1978 ◽  
Vol 76 (1) ◽  
pp. 63-84 ◽  
Author(s):  
W. J. HEITLER ◽  
COREY S. GOODMAN
Keyword(s):  
Action Potential ◽  
Branch Point ◽  
Peripheral Nerves ◽  
Action Potentials ◽  
Room Temperature ◽  
Initiation Site ◽  
Left And Right ◽  
Axon Branch ◽  
Spike Initiation ◽  
Dorsal Unpaired Median

Recordings were made from the metathoracic dorsal unpaired median neurone to the extensor tibiae muscle (DUMETi) in the locust. This is a bifurcating neurone with axons exiting both sideS of the ganglion, whose soma can support a full action potential. Four different spike types were recorded in the soma, each of which we associate with a different region of the neurone. These were (1) a soma (S) spike of 70-90 mV, (2) a neurite (N) spike of 20-40 mV, occurring between the axon hillock and axon branch point, (3) and (4) axon (A) spikes of 8–15 mV, occurring distal to the branch point on the left and right axons. Each of these regions must therefore have its own spike initiation site. At spike frequencies greater than about 10 Hz at room temperature or 1-5 Hz at 32 °C (the preferred environmental temperature of the locust) the S-spike may fail, revealing A-spikes, or more rarely N-spikes. A-spikes usually consist of two more-or-less separate components, Al and Ar, which can be correlated with action potentials in the left and right axon branches by recording spikes extracellularly in the peripheral nerves on each side. Occasionally single component A-spikes occur when an action potential is initiated in only one axon, and fails to propagate across the branch point to the contralateral axon. Thus, action potentials may occur independently in the branches of this bifurcating neurone. After unilateral axotomy only S-spikes and N-spikes are recorded, indicating that action potentials no longer fail to propagate across the branch point. Anatomical asymmetries in the axon branches of DUMETi have been correlated with physiological asymmetries recorded in the soma of the same neurone.

scholarly journals Axon Branch-Specific Semaphorin-1a Signaling in Drosophila Mushroom Body Development

2016 ◽  
Vol 10 ◽  
Author(s):  
Liesbeth Zwarts ◽  
Tim Goossens ◽  
Jason Clements ◽  
Yuan Y. Kang ◽  
Patrick Callaerts
Keyword(s):  
Mushroom Body ◽  
Body Development ◽  
Axon Branch

scholarly journals Overexpression of ATF3 or the combination of ATF3, c-Jun, STAT3 and Smad1 promotes regeneration of the central axon branch of sensory neurons but without synergistic effects

2015 ◽  
Vol 24 (23) ◽  
pp. 6788-6800 ◽  
Author(s):  
Nitish D. Fagoe ◽  
Callan L. Attwell ◽  
Dorette Kouwenhoven ◽  
Joost Verhaagen ◽  
Matthew R. J. Mason
Keyword(s):  
Sensory Neurons ◽  
Synergistic Effects ◽  
Axon Branch

Anatomical studies of central regeneration of an identified molluscan interneuron

1985 ◽  
Vol 226 (1243) ◽  
pp. 135-157 ◽  
Keyword(s):  
Target Cell ◽  
Lymnaea Stagnalis ◽  
Lucifer Yellow ◽  
Alternative Pathway ◽  
Anatomical Studies ◽  
Intracellular Injection ◽  
Neuritic Outgrowth ◽  
The Central Nervous System ◽  
Axon Branch ◽  
The Right

Regeneration of the giant interneuron R. Pe. D. 1 within the central nervous system of Lymnaea stagnalis was studied by intracellular injection of Lucifer Yellow. The major axon of R. Pe. D. 1 was severed by crushing the right–pleural–parietal connective and this initiates prolific sprouting from the proximal axon segment. Regeneration is highly specific in that neurites extend posteriorly across the crush site into regions of the c. n. s. where previously disconnected follower cells of R. Pe. D. 1 are located and project specifically to those nerve trunks that normally contain an axon branch of R. Pe. D. 1. Neurites also extend however, into regions of the anterior c. n. s. that are not normally occupied by R. Pe. D. 1 processes. This novel growth is a consistent consequence of lesioning the right pleural–parietal connective. Neuritic outgrowth is rapid, approximately 360–400 μm d -1 and processes reach the former target cell regions in the posterior c. n. s. within three or four days. The extent of the regenerative response shown by the interneuron was found to depend upon the site of lesion of its major axon within the c. n. s. Novel sprouting, for instance, was particularly extensive in preparations where the R. Pe. D. 1 axon was severed close to the soma but entirely absent when axotomy was carried out distally within the posterior c. n. s. Regenerating neurites are able to extend to the former target cell areas via an alternative pathway through the left side of the c. n. s. when regrowth via the normal right-hand route is prevented.

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