1. Analytic Solution for a Non-Axisymmetric Isothermal Dendrite - Non-axisymmetric Isothermal Dendrite,G. B. Mcfadden,S. R. Coriell,R. F. Sekerka
The Ivantsov solution for an isothermal paraboloid of revolution growing into a pure, supercooled melt provides a relation between the bulk supercooling and a dimensionless product (the Peclet number P ) of the growth velocity and tip radius of a dendrite. Horvay and Cahn generalized this axisymmetric analytical solution to a paraboloid with elliptical cross-section. They found that as the deviation of the dendrite cross-section from a circle increases, the two-fold symmetry of the interface shape causes a systematic deviation from the supercooling/Peclet number relation of the Ivantsov solution. To model dendritic growth in cubic materials, we find approximate solutions for paraboloids having perturbations with four-fold axial asymmetry....

2. Shape Parameter for a Non-Axisymmetric Isothermal Dendrite - Non-axisymmetric Isothermal Dendrite,G. B. Mcfadden,S. R. Coriell,R. F. Sekerka
In previous work, we found approximate solutions for paraboloids having perturbations with four-fold axial symmetry in order to model dendritic growth in cubic materials. These solutions provide self-consistent corrections through second order in a shape parameter ffl to the Peclet number -- supercooling relation of the Ivantsov solution. The parameter ffl is proportional to the amplitude of the four-fold correction to the dendrite shape, as measured from the Ivantsov paraboloid of revolution. We calculate ffl by comparing the dendrite tip shape to the portion of the equilibrium shape near the growth direction, [001], for anisotropic surface free energy of the form fl = fl 0 [1 + 4ffl...

3. MAPPING THERMAL GRADIENTS IN SCN USING A FAST FOURIER TRANSFORM ANALYSIS - BURCICA, CRISTINA IRINA
The principle goal of the present research is to understand the process of crystal dendrite growth. The main interest is to map the concentration and the temperature profile in the environment surrounding a crystal that is growing in the melt, using algorithms developed in MATLAB. Using optical interferometric techniques, it is clear that during the growth of dendrite crystals, a concentration gradient in the solution drives molecules toward the crystal. This results in the release of heat that is fed back into the temperature field of the melt. Solidification proceeds by driving the liquid/solid interface through a temperature gradient, at...

4. Exploring the Functional Significance of Dendritic Inhibition In Cortical Pyramidal Cells - M. W. Spratling and M. H. Johnson; Pyramidal Cells; M. W. Spratling; M. H. Johnson
Inhibitory synapses contacting the soma and axon initial segment are commonly presumed to participate in shaping the response properties of cortical pyramidal cells. Such an inhibitory mechanism has been explored in numerous computational models. However, the majority of inhibitory synapses target the dendrites of pyramidal cells, and recent physiological data suggests that this dendritic inhibition affects tuning properties. We describe a model that can be used to investigate the role of dendritic inhibition in the competition between neurons. With this model we demonstrate that dendritic inhibition significantly enhances the computational and representational properties of neural networks.

5. Structure of the vertical and horizontal system neurons of the lobula plate in Drosophila - Scott, Ethan K.; Raabe, Thomas; Luo, Liqun
The lobula plate in the optic lobe of the fly brain is a high-order processing center for visual information. Within the lobula plate lie a small number of giant neurons that are responsible for the detection of wide field visual motion. Although the structure and motion sensitivity of these cells have been extensively described in large flies, the system has not been described systematically in Drosophila. Here, we use the mosaic analysis with a repressible cell marker (MARCM) system to analyze a subset of these cells, the horizontal and vertical systems. Our results suggest that the Drosophila horizontal system is...

6. Why Have Dendrites? A Computational Perspective - Bartlett W. Mel
Introduction To delimit the scope of our discussion, we begin with the ull" hypothesis, which holds that dendrites exist strictly to increase the receptive surface area of a neuron, but do not otherwise contribute|or may even detract|from the information processing tasks of the neuron. The essence of this view is that the location of a synapse within the dendritic tree has relatively little importance for postsynaptic integration, which greatly simplies the rules needed for the construction and maintenance of a functioning axo-dendritic interface. As appealing as it may be, the strongest form of this hypothesis faces an immediate challenge. Specically, passive cable theory makes it clear that spatially...

7. Why Have Dendrites? A Computational Perspective - Bartlett W. Mel
Introduction To delimit the scope of our discussion, we begin with the ull" hypothesis, which holds that dendrites exist strictly to increase the receptive surface area of a neuron, but do not otherwise contribute|or may even detract|from the information processing tasks of the neuron. The essence of this view is that the location of a synapse within the dendritic tree has relatively little importance for postsynaptic integration, which greatly simplies the rules needed for the construction and maintenance of a functioning axo-dendritic interface. As appealing as it may be, the strongest form of this hypothesis faces an immediate challenge. Specically, passive cable theory makes it clear that spatially...

8. Dendrite - Beckwith, Frank A. (1876-1951);
Dendrite Emory John Aug. 26, 1950.

9. Dendrite
Dendrite--Marion Killpack. Worm trails--Emory John.

10. Dendrite
Dendrite--Marion Killpack. Worm trails--Emory John.

11. Signal Detection in Noisy Weakly-Active Dendrites - Amit Manwani,Christof Koch
Here we derive measures quantifying the information loss of a synaptic signal due to the presence of neuronal noise sources, as it electrotonically propagates along a weakly-active dendrite . We model the dendrite as an infinite linear cable, with noise sources distributed along its length. The noise sources we consider are thermal noise, channel noise arising from the stochastic nature of voltage-dependent ionic channels (K + and Na + ) and synaptic noise due to spontaneous background activity. We assess the efficacy of information transfer using a signal detection paradigm where the objective is to detect the presence/absence of a presynaptic spike from the post-synaptic membrane voltage. This allows us to analytically assess the...

12. Chain Of Dendrites Openly Unbounded From Bellow - David Op Ela,Pavel Pyrih,S Amal
. We consider an ordering with respect to open mappings on the class of all dendrites and construct a chain of dendrites which does not have a lower bound answering negatively a question of its existence. 1. Preliminaries. All spaces considered in this paper are assumed to be metric. A continuum means a nonempty compact connected metric space. A simple closed curve is any space which is homeomorphic to the unit circle. A dendrite means a locally connected continuum containing no simple closed curve. A mapping means a continuous function. A surjective mapping f : X ! Y is said to be: -- open provided that for each open subset...

13. An Example Of Openly Minimal Dendrite - Pavel Pyrih,David Op Ela,S Amal
. J. J. Charatonik, W. J. Charatonik and J. R. Prajs asked a question if each openly minimal dendrite is homeomorphic to each its open image. We give a negative answer in Proposition 3.5. 1. Openly minimal dendrite. All spaces considered in this paper are assumed to be metric. A continuum means a nonempty compact connected metric space. A simple closed curve is any space which is homeomorphic to the unit circle. A dendrite means a locally connected continuum containing no simple closed curve. A mapping means a continuous function. A surjective mapping f : X ! Y is said to be: -- open provided that for each open subset...

14. Possible Functional Roles of the Bipartite Dendrites of Pyramidal Cells - Ralf Moller,Horst--michael Gro
A theory about the possible functional roles of the bipartite dendrites of cortical pyramidal cells is presented that tries to fuse aspects of both Cardinal Cell Theory and Assembly Theory. The article treats resulting functional differences of both dendritic pathways in conjunction with an hypothesis concerning the existence of two activity ranges. The model includes a three--rule system of self--organization. 1 Cortical architecture The main cortical cell type are pyramidal cells. These cells show a typical dendritic morphology. An apical dendrite originates from the top of the cell body and runs perpendicular to the cortical surface into direction of the pia mater. These dendrites are contacted by synapses from cortico--cortical...

15. Possible Functional Roles of the Bipartite Dendrites of Pyramidal Cells - Ralf Moller,Horst--michael Gro
A theory about the possible functional roles of the bipartite dendrites of cortical pyramidal cells is presented that tries to fuse aspects of both Cardinal Cell Theory and Assembly Theory. The article treats resulting functional differences of both dendritic pathways in conjunction with an hypothesis concerning the existence of two activity ranges. The model includes a three--rule system of self--organization. 1 Cortical architecture The main cortical cell type are pyramidal cells. These cells show a typical dendritic morphology. An apical dendrite originates from the top of the cell body and runs perpendicular to the cortical surface into direction of the pia mater. These dendrites are contacted by synapses from cortico--cortical...

16. Possible Functional Roles of the Bipartite Dendrites of Pyramidal Cells - Ralf Moller,Horst--michael Gro
A theory about the possible functional roles of the bipartite dendrites of cortical pyramidal cells is presented that tries to fuse aspects of both Cardinal Cell Theory and Assembly Theory. The article treats resulting functional differences of both dendritic pathways in conjunction with an hypothesis concerning the existence of two activity ranges. The model includes a three--rule system of self--organization. 1 Cortical architecture The main cortical cell type are pyramidal cells. These cells show a typical dendritic morphology. An apical dendrite originates from the top of the cell body and runs perpendicular to the cortical surface into direction of the pia mater. These dendrites are contacted by synapses from cortico--cortical...

17. Possible Functional Roles of the Bipartite Dendrites of Pyramidal Cells - Ralf Moller,Horst--michael Gro
A theory about the possible functional roles of the bipartite dendrites of cortical pyramidal cells is presented that tries to fuse aspects of both Cardinal Cell Theory and Assembly Theory. The article treats resulting functional differences of both dendritic pathways in conjunction with an hypothesis concerning the existence of two activity ranges. The model includes a three--rule system of self--organization. 1 Cortical architecture The main cortical cell type are pyramidal cells. These cells show a typical dendritic morphology. An apical dendrite originates from the top of the cell body and runs perpendicular to the cortical surface into direction of the pia mater. These dendrites are contacted by synapses from cortico--cortical...

18. Possible Functional Roles of the Bipartite Dendrites of Pyramidal Cells - Ralf Moller,Horst--michael Gro
A theory about the possible functional roles of the bipartite dendrites of cortical pyramidal cells is presented that tries to fuse aspects of both Cardinal Cell Theory and Assembly Theory. The article treats resulting functional differences of both dendritic pathways in conjunction with an hypothesis concerning the existence of two activity ranges. The model includes a three--rule system of self--organization. 1 Cortical architecture The main cortical cell type are pyramidal cells. These cells show a typical dendritic morphology. An apical dendrite originates from the top of the cell body and runs perpendicular to the cortical surface into direction of the pia mater. These dendrites are contacted by synapses from cortico--cortical...

19. Cortical Region Interactions And The Functional Role Of Apical Dendrites - M. W. Spratling
The basal and distal apical dendrites of pyramidal cells occupy distinct cortical layers and are targeted by axons originating in different cortical regions. Hence, apical and basal dendrites receive information from distinct sources. Physiological evidence suggests that this anatomically observed segregation of input sources may have functional significance. This possibility has been explored in various connectionist models that employ neurons with functionally distinct apical and basal compartments. A neuron in which separate sets of inputs can be integrated independently has the potential to operate in a variety of ways which are not possible for the conventional model of a neuron in which all inputs are treated equally....

20. Cortical Region Interactions And The Functional Role Of Apical Dendrites - M. W. Spratling
The basal and distal apical dendrites of pyramidal cells occupy distinct cortical layers and are targeted by axons originating in different cortical regions. Hence, apical and basal dendrites receive information from distinct sources. Physiological evidence suggests that this anatomically observed segregation of input sources may have functional significance. This possibility has been explored in various connectionist models that employ neurons with functionally distinct apical and basal compartments. A neuron in which separate sets of inputs can be integrated independently has the potential to operate in a variety of ways which are not possible for the conventional model of a neuron...

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