Ion Projection Research Articles

Can divergent connectivity generate reliable sparse activity patterns?

Event Abstract Back to Event Can divergent connectivity generate reliable sparse activity patterns? The connectivity in the brain can be highly convergent and highly divergent. In the olfactory system of insects, for example, the connections from olfactory receptor neurons to projection (PNs) and local neurons (LNs) in the antennal lobe, the primary center for olfactory information processing, are highly convergent. The connections from the PNs to the Kenyon cells (KCs) in the secondary center of processing, the mushroom bodies, are, on the other hand, highly divergent. While the role of convergence and its properties in improving signal to noise ratios are if not fully understood at least generally accepted, the role of divergent connectivities is less clear. It has been suggested by us and others that divergence may serve to generate well separated, sparse activity patterns which are known to be beneficial for recognition (classification) and memory formation. In this work we analyze general implications of divergent connectivity in the framework of unspecific (randomly connected) feedforward networks of generic (McCulloch-Pitts) neurons. We find that the distribution for the number of active neurons in the target area is very skewed with large probabilities for no response as well as a fat tail of non-zero probabilities for overwhelming responses of many neurons. The results imply that in the example of the locust olfactory system, divergent connections by themselves, cannot generate the desirable, and experimentally observed, sparse activity patterns if the observed high density of PN-KC connections is correct. This apparent contradiction can be resolved by feedforward gain-control, which may be implemented by the antennal lobe - lateral horn - mushroom body pathway. The remainder of the work is dedicated to elaborating a hypothesis why nature may have chosen a much more costly solution - dense PN-KC connections and feedforward gain control - over a much simpler solution - sparse PN-KC connections. Our results are applicable to many questions in neuroscience as divergent connections are ubiquitous, another prominent example being the connections from the entorhinal cortex to the dentate gyrus in the mammalian hippocampal formation. This work was partially funded by the Biotechnology and Biological Sciences Research Council (grant number BB/F005113/1). Conference: Computational and systems neuroscience 2009, Salt Lake City, UT, United States, 26 Feb - 3 Mar, 2009. Presentation Type: Poster Presentation Topic: Poster Presentations Citation: (2009). Can divergent connectivity generate reliable sparse activity patterns?. Front. Syst. Neurosci. Conference Abstract: Computational and systems neuroscience 2009. doi: 10.3389/conf.neuro.06.2009.03.008 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 Jan 2009; Published Online: 29 Jan 2009. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Google Google Scholar PubMed Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Postpositional Elements and Nominal Extended Projections in Korean

Postpositional Elements and Nominal Extended Projections in Korean

Koniocellular projections and hand-assisted blindsight

Koniocellular projections and hand-assisted blindsight

『Silver World』, The projection and organization of reality

『Silver World』, The projection and organization of reality

Philosophic projections

Philosophic projections

Projections of Peronism in Argentine autobiography, biography and fiction

Projections of Peronism in Argentine autobiography, biography and fiction

Reviews Of Acoustical Patents

Abstract

Superconductivity in curved space-time and Cattaneo's projection method

Superconductivity in curved space-time and Cattaneo's projection method

Projection and pragmatics: Two comments

Projection and pragmatics: Two comments

基于球面透视投影约束的全景环形透镜畸变校正

基于球面透视投影约束的全景环形透镜畸变校正

Surfaces in $\mathbb{R}^4$ and their projections to 3-spaces

Surfaces in $\mathbb{R}^4$ and their projections to 3-spaces

Metrics in the sphere of a C*-module

Fil: Andruchow, Esteban. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Saavedra 15. Instituto Argentino de Matematica Alberto Calderon; Argentina

Hiperplasia epitelial focal (doença de Heck) em descendente de índios brasileiros: relato de caso

A hiperplasia epitelial focal, ou doenca de Heck, e uma enfermidade rara, benigna, que afeta a mucosa oral de criancas e adultos jovens de diversas regioes do mundo e em diferentes grupos etnicos, como indigenas e esquimos. Apresenta correlacao com o papilomavirus humano (HPV) no qual os tipos 13 e 32 tem sido consistentemente detectados nessas lesoes. Este artigo relata um caso de uma paciente de 18 anos de idade, descendente de indios potiguares, que compareceu ao servico de estomatologia da Universidade Federal do Rio Grande do Norte (UFRN), exibindo lesoes bem definidas, arredondadas, planas, localizadas em cavidade oral, com tempo de evolucao de aproximadamente dois anos. As lesoes foram submetidas a biopsias incisionais, constatado-se no exame histopatologico alteracoes epiteliais, como acantose, cristas epiteliais em forma de taco de golfe alem de celulas mitosoides. Esses achados histopatologicos foram compativeis com a hipotese clinica de hiperplasia epitelial focal (doenca de Heck).

Heated falling films

We present new insights and results for the problem of a film falling down a heated wall: (i) treatment of a mixed heat flux boundary condition on the substrate; (ii) development of a long-wave theory for large Péclet numbers; (iii) refined treatment of the energy equation based on a high-order Galerkin projection in terms of polynomial test functions which satisfy all boundary conditions; (iv) time-dependent computations for the free-surface height and interfacial temperature; (v) numerical solution of the full energy equation; (vi) demonstration of the existence of a thermal boundary layer at the front stagnation point of a solitary pulse; (vii) development of models that prevent negative temperatures and are in good agreement with the numerical solution of the full energy equation.

Long Range Projections

Long Range Projections

VOLUME INEQUALITIES FOR Lp-JOHN ELLIPSOIDS AND THEIR DUALS

AbstractIn this paper, we establish some inequalities among the Lp-centroid body, the Lp-polar projection body, the Lp-John ellipsoid and its dual, which are the strengthened version of known results. We also prove inequalities among the polar of the Lp-centroid body, the Lp-polar projection body, the Lp-John ellipsoid and its dual.

A Note on the Existence of Shape-Preserving Projections

A Note on the Existence of Shape-Preserving Projections

Ben-Ner's Moby Dick and Melville's Mechanism of Projection

Ben-Ner's Moby Dick and Melville's Mechanism of Projection

Determining the Undetermined: Derrida's "University Without Condition"

In "The University Without Condition" Derrida imagines a university-to-come. His projection repeats familiar Enlightenment theses concerning freedom of thought. But his insistence upon the university's exemption from conditions bleeds over into the way he conceptualizes his own argument. He renounces any account of determinations and interests in the formation both of the university and of those who would inhibit its freedom. This leaves him with no means to explain how the university-to-come could be freed from these constraints, and limits him to a technology of miracles as the only cognizable means for achieving the changes he so fervently wishes for.

ヒューマンインタフェースとバーチャルリアリティ ＰＡＬＭｂｉｔ：掌への光投影を利用した身体インタフェース

We propose a projection-based wearable system,PALMbit,which enables user's palms to input control events and to output graphic information.The I/O interface for wearable computers depends largely on their practical applications.In the proposed system,we developed both an input and output method for controlling digital appliances; an optical projection onto the user's palm,which is registered by image processing,and a gesture interface based on nger actions.By projecting an image of a virtual remote controller onto the user's palm,the user is able to control digital equipment intuitively using his/her own mental body image and a haptic feedback.Experimental results with a prototype application on the proposed I/O methods show that the naturalness of images projected onto palms is superior to that of HMD-based images.