Axonal branching patterns of nucleus accumbens neurons in the rat

2010 ◽  
Vol 518 (22) ◽  
pp. 4649-4673 ◽  
Author(s):  
Anushree Tripathi ◽  
Lucía Prensa ◽  
Carolina Cebrián ◽  
Elisa Mengual
Keyword(s):  
Nucleus Accumbens ◽  
Axonal Branching ◽  
Branching Patterns

scholarly journals Axonal Branching Patterns as Sources of Delay in the Mammalian Auditory Brainstem: A Re-Examination

2011 ◽  
Vol 31 (8) ◽  
pp. 3016-3031 ◽  
Author(s):  
S. Karino ◽  
P. H. Smith ◽  
T. C. T. Yin ◽  
P. X. Joris
Keyword(s):  
Auditory Brainstem ◽  
Axonal Branching ◽  
Branching Patterns

Axonal branching patterns and funicular trajectories of raphespinal sympathoinhibitory neurons

1985 ◽  
Vol 53 (3) ◽  
pp. 759-772 ◽  
Author(s):  
S. F. Morrison ◽  
G. L. Gebber
Keyword(s):  
Action Potentials ◽  
Threshold Current ◽  
Spinal Segment ◽  
Axonal Branching ◽  
Thoracic Level ◽  
Axonal Projections ◽  
Thoracic Spinal ◽  
Spike Triggered Averaging ◽  
Branching Patterns ◽  
Antidromic Responses

We studied axonal branching patterns and funicular trajectories of cat medullary raphespinal neurons with spontaneous activity related to inferior cardiac postganglionic sympathetic nerve discharge (as demonstrated with spike-triggered averaging). These neurons were excited by raising carotid sinus pressure. We have classified these neurons as sympathoinhibitory in function and refer to them here as RS neurons. Microstimulation of the second thoracic spinal segment (T2) antidromically activated RS neurons (as determined with time-controlled collision of spontaneous and evoked action potentials). The longest-latency antidromic responses were elicited with the lowest-threshold current from sites in the intermediolateral nucleus (IML). This observation suggests that RS neurons innervated IML. Most RS neurons activated from T2 were also antidromically activated by stimulation of a more caudal thoracic spinal segment (T6 or T12). Time-controlled collision of action potentials evoked by stimulation at two thoracic levels allowed us to distinguish activation of an axonal branch in T2 from that of the main axon coursing through T2 to the more caudal thoracic level. Of those RS axons that branched in T2, 78% descended at least as far caudal as T6, whereas 65% reached T12. The axonal projections of other RS neurons that innervated T2 were restricted to no more than two consecutive thoracic spinal segments (as determined by stimulation in T3). Antidromic mapping of T2 further revealed that the axons of RS neurons coursed through the dorsolateral, ventral, or ventrolateral funiculus to innervate the ipsilateral and/or contralateral IML. The conduction velocities of dorsolateral and ventral RS axons indicated that they were finely myelinated. The data demonstrate the existence of RS neurons with restricted and widespread axonal branching patterns, thereby supporting the view that the medullary raphe complex is capable of regional as well as global inhibitory control over spinal sympathetic outflow.

Axonal branching patterns of ventral pallidal neurons in the rat

2012 ◽  
Vol 218 (5) ◽  
pp. 1133-1157 ◽  
Author(s):  
Anushree Tripathi ◽  
Lucía Prensa ◽  
Elisa Mengual
Keyword(s):  
Axonal Branching ◽  
Branching Patterns

scholarly journals A Generative Growth Model for Thalamocortical Axonal Branching in Primary Visual Cortex

2018 ◽  
Author(s):  
Pegah Kassraian Fard ◽  
Michael Pfeiffer ◽  
Roman Bauer
Keyword(s):  
Ocular Dominance ◽  
Length Distribution ◽  
Local Environment ◽  
Asymmetry Index ◽  
Generative Model ◽  
Segment Length ◽  
Target Area ◽  
Large Variability ◽  
Axonal Branching ◽  
Branching Patterns

AbstractAxonal morphology displays large variability and complexity, yet the canonical regularities of the cortex suggest that such wiring is based on the repeated initiation of a small set of genetically encoded rules. Extracting underlying developmental principles can hence shed light on what genetically encoded instructions must be available during cortical development. Within a generative model, we investigate growth rules for axonal branching patterns in cat area 17, originating from the lateral geniculate nucleus of the thalamus. This target area of synaptic connections is characterized by extensive ramifications and a high bouton density, characteristics thought to preserve the spatial resolution of receptive fields and to enable connections for the ocular dominance columns. We compare individual and global statistics, such as a newly introduced asymmetry index and the global segment-length distribution, of generated and real branching patterns as the benchmark for growth rules. We show that the proposed model surpasses the statistical accuracy of the Galton-Watson model, which is the most commonly employed model for biological growth processes. In contrast to the Galton-Watson model, our model can recreate the log-normal segment-length distribution of the experimental dataset and is considerably more accurate in recreating individual axonal morphologies. To provide a biophysical interpretation for statistical quantifications of the axonal branching patterns, the generative model is ported into the physically accurate simulation framework of Cx3D. In this simulation environment we demonstrate how the proposed growth process can be formulated as an interactive process between genetic growth rules and chemical cues in the local environment.

Age-Dependent Changes in Axonal Branching of Single Locus Coeruleus Neurons Projecting to Two Different Terminal Fields

2000 ◽  
Vol 84 (2) ◽  
pp. 1120-1122 ◽  
Author(s):  
Tetsuya Shirokawa ◽  
Yoshiyuki Ishida ◽  
Ken-Ichi Isobe
Keyword(s):  
Frontal Cortex ◽  
Locus Coeruleus ◽  
Time Course ◽  
Single Locus ◽  
Antidromic Activation ◽  
Axonal Branching ◽  
Branching Patterns ◽  
Age Dependent ◽  
F344 Rats ◽  
Male F344 Rats

Age-dependent changes in the axonal branching patterns of single locus coeruleus neurons, which innervate both the frontal cortex and hippocampus dentate gyrus, have been studied in male F344 rats. We used an electrophysiological approach involving antidromic activation to differentiate single from multi-threshold locus coeruleus neurons in each terminal field with age (7–27 mo of age). Most of these neurons have a single threshold in the young rats, whereas in the older brains, the neurons have multi-threshold responses. This implies an increased amount of axonal branching in the older brains. The time course of the increase differs in the two terminal fields, suggesting that the degree of plasticity or age-dependent increase in branching can differ across terminal fields.

Variability in the Structure of An Identified Interneurone in Isogenic Clones of Locusts

1983 ◽  
Vol 103 (1) ◽  
pp. 47-54
Author(s):  
JOHN D. STEEVES ◽  
KEIR G. PEARSON
Keyword(s):  
Schistocerca Gregaria ◽  
Genotypic Differences ◽  
Movement Detector ◽  
Synaptic Connections ◽  
Epigenetic Factors ◽  
Axonal Branching ◽  
Monosynaptic Connection ◽  
Branching Patterns ◽  
Single Clone ◽  
Contralateral Movement

Several studies have shown that there can be considerable variability in the morphology of identified neurones. In a recent investigation (Pearson & Goodman, 1979) a great degree of variability was observed in the axon branching patterns of the descending contralateral movement detector (DCMD) interneurones of locusts. Corresponding to the variation in the structure of DCMD was a large variation in the synaptic connections made by this interneurone; the absence of a monosynaptic connection always correlated with the lack of the appropriate axonal branch of DCMD. Since this variability could be related to genotypic differences, we investigated the structure and synaptic connections of DCMD in individuals from several different isogenic clones of the locust Schistocerca gregaria. Within a single group of clones the variability in the axonal branching patterns and synaptic connections of DCMD was generally less than that between different clones or in sexually reproduced control animals. More significantly, a few of the clonal groups had consistently unique branching patterns and concomitant synaptic connections. Nevertheless, there was still some variability in the structure of DCMD within each clone. We conclude from these observations that differences in genotype can influence the morphology of individual neurones at the relatively refined level of axonal branching patterns and consequently the neurone's synaptic connections. However, due to the variability of DCMD structure within a single clone, epigenetic factors must also determine the pattern of axonal branching.

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