Tree asymmetry—A sensitive and practical measure for binary topological trees

Pelt, Jaap van; Uylings, H.B.M.; Verwer, R.W.H.; Pentney, Roberta J.; Woldenberg, Michael J.

doi:10.1007/bf02459929

Cited by 103 publications

(106 citation statements)

References 24 publications

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“…The number of subsequent nodes in both subtrees can be used to compute the so-called partition asymmetry index, whose mean value over all nodes can be taken as a measure of tree asymmetry (31,95). Various alternative measures of asymmetry have been proposed, in particular ''caulescence'' (weighted partition asymmetry of nodes along the main path, maximizing a given metric), which provides a clearer functional consequence (96).…”

Section: Tree Quantificationmentioning

confidence: 99%

Neuron tracing in perspective

2010

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The study of the structure and function of neuronal cells and networks is of crucial importance in the endeavor to understand how the brain works. A key component in this process is the extraction of neuronal morphology from microscopic imaging data. In the past four decades, many computational methods and tools have been developed for digital reconstruction of neurons from images, with limited success. As witnessed by the growing body of literature on the subject, as well as the organization of challenging competitions in the field, the quest for a robust and fully automated system of more general applicability still continues. The aim of this work, is to contribute by surveying recent developments in the field for anyone interested in taking up the challenge. Relevant aspects discussed in the article include proposed image segmentation methods, quantitative measures of neuronal morphology, currently available software tools for various related purposes, and morphology databases. ' 2010 International Society for Advancement of Cytometry

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Section: Tree Quantificationmentioning

confidence: 99%

Neuron tracing in perspective

2010

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“…2b, Table I). The lateral distribution of dendritic elements along the apical dendritic tree was estimated using the tree asymmetry index (Van Pelt et al, 1992). We found no significant changes in the tree asymmetry index, neither during normal development (P10 trkB +/+ : 0.47 ± 0.12; P14 trkB +/+ : 0.48 ± 0.05, respectively) nor as a result of trkB deletion (P14 trkB -/-: 0.51 ± 0.06 (means ± s.d., tested with ANOVA, Table I).…”

Section: Pc Morphologymentioning

confidence: 99%

“…A dendritic element was defined as the connection either between two bifurcations, the soma and the first bifurcation or the last bifurcation and the tip of the dendrite. The asymmetry of the largest dendritic tree of each PC was characterized by the "tree asymmetry index" (Van Pelt et al, 1992), calculated as: with r and s being the number of dendritic elements on the right-hand or left-hand side, respectively. For the centrifugal branch order analysis after each bifurcation, the branch order of both daughter dendritic elements increases by one.…”

Section: Purkinje Cell Morphometrymentioning

confidence: 99%

Requirement of TrkB for synapse elimination in developing cerebellar Purkinje cells

et al. 2007

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The receptor tyrosine kinase TrkB and its ligands, brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT-4/5), are critically important for growth, survival and activity-dependent synaptic strengthening in the central nervous system. These TrkB-mediated actions occur in a highly cell-type specific manner. Here we report that cerebellar Purkinje cells, which are richly endowed with TrkB receptors, develop a normal morphology in trkB-deficient mice. Thus, in contrast to other types of neurons, Purkinje cells do not need TrkB for dendritic growth and spine formation. Instead, we find a moderate delay in the maturation of GABAergic synapses and, more importantly, an abnormal multiple climbing fiber innervation in Purkinje cells in trkB-deficient mice. Thus, our results demonstrate an involvement of TrkB receptors in synapse elimination and reveal a new role for receptor tyrosine kinases in the brain.

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“…Branching asymmetry index-Branching asymmetry was determined according to van Pelt et al, (1992). Briefly, for a given tree X n with n terminal segments, the dendritic tree asymmetry index A t (X n ) is defined as 1/1-n times the sum of all patrician indices, A p (r j , s j ) from j = 1 to n−1.…”

Section: Analysis Of Specific Dendritic Architecture Featuresmentioning

confidence: 99%

Tiling among stereotyped dendritic branches in an identified Drosophila motoneuron

Vonhoff

Duch

2010

J of Comparative Neurology

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Different types of neurons can be distinguished by the specific targeting locations and branching patterns of their dendrites, which form the blueprint for wiring the brain. Unraveling which specific signals control different aspects of dendritic architecture, such as branching and elongation, pruning and cessation of growth, territory formation, tiling, and self-avoidance requires a quantitative comparison in control and genetically manipulated neurons. The highly conserved shapes of individually identified Drosophila neurons make them well suited for the analysis of dendritic architecture principles. However, to date it remains unclear how tightly dendritic architecture principles of identified central neurons are regulated. This study uses quantitative reconstructions of dendritic architecture of an identified Drosophila flight motoneuron (MN5) with a complex dendritic tree, comprising more than 4,000 dendritic branches and 6 mm total length. MN5 contains a fixed number of 23 dendritic subtrees, which tile into distinct, nonoverlapping volumes of the diffuse motor neuropil. Across-animal comparison and quantitative analysis suggest that tiling of the different dendritic subtrees of the same neuron is caused by competitive and repulsive interactions among subtrees, perhaps allowing different dendritic compartments to be connected to different circuit elements. We also show that dendritic architecture is similar among different wildtype and GAL4 driver fly lines. Metric and topological dendritic architecture features are sufficiently constant to allow for studies of the underlying control mechanisms by genetic manipulations. Dendritic territory and certain topological measures, such as tree compactness, are most constant, suggesting that these reflect the intrinsic molecular identity of the neuron. INDEXING TERMSdendrite; dendritic arborization; repulsion; motoneuron; tiling; topology; avoidance The remarkably diverse dendritic architectures of different types of neurons determine the types and numbers of inputs a neuron receives (Connors and Regehr, 1996; Cory et al., 2009). Furthermore, dendritic structure can affect the integration and computation of synaptic input information (Single and Borst, 1998; Häusser et al., 2000, Koch andSegev, 2000; London and Häusser, 2005 Additional supporting information may be found in the online version of this article. HHS Public Access Author ManuscriptAuthor Manuscript Author Manuscript Author ManuscriptStrikingly similar morphologies exist for the same types of vertebrate (e.g., pyramidal, Purkinje, or basket cells) and invertebrate neurons. In fact, dendritic morphology is a major criterion for the classification of neurons. Moreover, individually identified neurons with distinct morphologies exist in many invertebrate preparations (Mendenhall and Murphey, 1974;Ikeda et al., 1980;Thomas and Wyman, 1984; Levine, 2000, Libersat andDuch, 2002). These neurons can be unambiguously identified in different animals of the same species, only one such neuron exists per n...

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Tree asymmetry—A sensitive and practical measure for binary topological trees

Cited by 103 publications

References 24 publications

Neuron tracing in perspective

Neuron tracing in perspective

Requirement of TrkB for synapse elimination in developing cerebellar Purkinje cells

Tiling among stereotyped dendritic branches in an identified Drosophila motoneuron

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