Mathematics of Hebbian attractors

AbstractThe concept of an attractor in a mathematical dynamical system is reviewed. Emphasis is placed on the distinction between a cell assembly, the corresponding attractor, and the attractor dynamics. The biological significance of these entities is discussed, especially the question of whether the representation of the stimulus requires the full attractor dynamics, or merely the cell assembly as a set of reverberating neurons. Comparison is made to Freeman's study of dynamic patterns in olfaction.

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Quantitative cell fusion: the fusion sensitivity (FS) potential

Journal of Cell Science ◽

10.1242/jcs.49.1.87 ◽

1981 ◽

Vol 49 (1) ◽

pp. 87-97

Author(s):

D. Rohme

Keyword(s):

Cell Line ◽

Cell Fusion ◽

Cell Lines ◽

Dose Response ◽

Sendai Virus ◽

Biological Significance ◽

Diploid Cell ◽

Mammalian Cell Lines ◽

Virus Dose ◽

A Cell

The dose response of Sendai virus-induced cell fusion was studied in 10 mammalian cell lines, comprising 5 continuous and 5 diploid cell lines originating from 5 species. The extent of fusion was calculated using a parameter directly proportional to the number of fusion events (t-parameter). At lower levels of fusion the dose response was found to be based on the same simple kinetic rules in all cell lines and was defined by the formula: t = FS. FAU/(I + FS. FAU), where FS (fusion sensitivity) is a cell-specific constant of the fusion rate and FAU (fusion activity units) is the virus dose. The FS potential of a cell line was determined as the linear regression coefficient of the fusion index (t/(I - t)) on the virus dose. At higher levels of fusion, when the fusion extent reached cell-line-specific maximal levels, the dose response was not as uniform. In general, and particularly in the cases of the diploid cell lines, these maximal levels were directly proportional to the FS potentials. Thus, it was concluded that the FS potential is the basic quantitative feature, which expresses the cellular fusion efficiency. The fact that FS varied extensively between cell lines, but at the same time apparently followed certain patterns (being higher in continuous compared to diploid cell lines and being related to the species of origin of the cells), emphasizes it biological significance as well as its possible usefulness in studies of the efficiency of various molecular interactions in the cell membrane/cytoskeleton system.

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Teaching Real Data Interpretation with Models (TRIM): Analysis of Student Dialogue in a Large-Enrollment Cell and Developmental Biology Course

CBE—Life Sciences Education ◽

10.1187/cbe.15-11-0239 ◽

2016 ◽

Vol 15 (2) ◽

pp. ar17 ◽

Cited By ~ 11

Author(s):

Patricia Zagallo ◽

Shanice Meddleton ◽

Molly S. Bolger

Keyword(s):

Cell Biology ◽

Biological Significance ◽

Real Data ◽

Data Interpretation ◽

Biological Data ◽

Scientific Practices ◽

Student Dialogue ◽

Audio Recordings ◽

A Cell ◽

Large Enrollment

We present our design for a cell biology course to integrate content with scientific practices, specifically data interpretation and model-based reasoning. A 2-yr research project within this course allowed us to understand how students interpret authentic biological data in this setting. Through analysis of written work, we measured the extent to which students’ data interpretations were valid and/or generative. By analyzing small-group audio recordings during in-class activities, we demonstrated how students used instructor-provided models to build and refine data interpretations. Often, students used models to broaden the scope of data interpretations, tying conclusions to a biological significance. Coding analysis revealed several strategies and challenges that were common among students in this collaborative setting. Spontaneous argumentation was present in 82% of transcripts, suggesting that data interpretation using models may be a way to elicit this important disciplinary practice. Argumentation dialogue included frequent co-construction of claims backed by evidence from data. Other common strategies included collaborative decoding of data representations and noticing data patterns before making interpretive claims. Focusing on irrelevant data patterns was the most common challenge. Our findings provide evidence to support the feasibility of supporting students’ data-interpretation skills within a large lecture course.

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Interaction of soluble fibroblast surface antigen with fribrinogen and fibrin.

Journal of Experimental Medicine ◽

10.1084/jem.141.2.497 ◽

1975 ◽

Vol 141 (2) ◽

pp. 497-501 ◽

Cited By ~ 264

Author(s):

E Ruoslahti ◽

A Vaheri

Keyword(s):

Human Plasma ◽

Low Temperatures ◽

Serum Proteins ◽

Biological Significance ◽

Cell Type ◽

Fold Enrichment ◽

Glycoprotein Antigen ◽

A Cell ◽

Cell Type Specific ◽

Cold Insoluble Globulin

A cell-type specific glycoprotein antigen (SFA) from fibroblast surface appears in human plasma and serum. The amount of SFA in serum was reduced if the blood coagulation clot was removed at a low temperature. SFA could be bound to Sepharose-conjugated fibrinogen and to fibrin powder at 0 degrees C and was subsequently released when the temperature was elevated to plus 37 degrees C. This procedure resulted in a 10-fold enrichment of SFA relative to other serum proteins. SFA was found to be concentrated in the cryoprecipitate fraction of human plasma and was copurified with the cold insoluble globulin (CIG) with procedures published for the purification of the latter component. SFA/CIG is not soluble at low temperatures as such and its appearance in the cryoprecipitate fraction of plasma is likely to be due to its affinity to cryofibrinogen evident from these experiments. The biological significance of the interaction of fibroblast surface SFA moleculres with fibrin(ogen) is not known.

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Design and Evaluation of a Cell Microencapsulating Device for Cell Assembly Technology

Journal of Bioactive and Compatible Polymers ◽

10.1177/0883911509103329 ◽

2009 ◽

Vol 24 (1_suppl) ◽

pp. 48-62 ◽

Cited By ~ 31

Author(s):

Rui Yao ◽

Renji Zhang ◽

Xiaohong Wang

Keyword(s):

Cell Encapsulation ◽

Diameter Distribution ◽

Cell Assembly ◽

Controlled Assembly ◽

Electrode Distance ◽

High Viability ◽

A Cell ◽

Assembly Technology ◽

Adipose Derived Stem Cell ◽

Cacl2 Solution

A cell encapsulation device based on the principle of high-voltage dispersion technology was designed and constructed. The parameters that influenced the formation of cell microcapsules, such as; voltage, push speed, electrode distance, and syringe size were analyzed and optimized. Unlike the traditional cell microencapsulating devices, both of the electrodes were separated from the CaCl2 solution in this device, which simplified the procedure of keeping the operation within a sanitary environment. Integrated adipose derived stem cell (ADSC) microcapsules with smooth surface and consistent diameter distribution were prepared. After 1-week in culture as a microcapsule and 3 days assembled in a construct, the ADSCs maintained a high viability and significant proliferation that established a favorable basis for the controlled assembly of cell microcapsules.

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Hypothetical Double-Helical Poly(A) Formation in a Cell and Its Possible Biological Significance

IUBMB Life ◽

10.1080/713803577 ◽

1999 ◽

Vol 48 (6) ◽

pp. 581-584 ◽

Cited By ~ 28

Author(s):

Margarita Zarudnaya ◽

Dmytro Hovorun

Keyword(s):

Biological Significance ◽

A Cell

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Somatic DNA recombination in the brainThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y05-099 ◽

2006 ◽

Vol 84 (3-4) ◽

pp. 319-324

Author(s):

Toyoki Maeda ◽

Saburo Sakoda ◽

Tomokazu Suzuki ◽

Naoki Makino

Keyword(s):

Dna Recombination ◽

Biological Significance ◽

Indirect Evidence ◽

Dna Rearrangement ◽

Special Issue ◽

Recombination Activity ◽

A Cell ◽

The Brain ◽

Oriented Approach ◽

Selection Of

Possible somatic DNA recombination in the brain has been investigated by attempting to capture direct or indirect evidence of it. Until recently, the biological significance of the DNA event, the genes is involved in the recombination, or even whether the event actually occurs in the brain has remained unclear. The DNA-rearranged locus-oriented approach and the recombination activity-oriented approach have mutually contributed to the elucidation of the biological features of extra-immune system somatic DNA recombination. There have been only 2 loci proposed for the candidate, one is a repetitive sequence and the other DNA recombination is nonrepetitive locus. This review states conventional concepts and discussions chronologically and finally to the newest aspects of DNA rearrangement in the brain.

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Network remodeling induced by transcranial brain stimulation: A computational model of tDCS-triggered cell assembly formation

10.1101/466136 ◽

2018 ◽

Cited By ~ 1

Author(s):

Han Lu ◽

Júlia V. Gallinaro ◽

Stefan Rotter

Keyword(s):

Recurrent Network ◽

Inhibitory Neurons ◽

Brain Diseases ◽

Cell Assembly ◽

Excitatory Synapses ◽

Non Invasive ◽

Duty Cycles ◽

Transcranial Brain Stimulation ◽

A Cell ◽

The Impact

AbstractTranscranial direct current stimulation (tDCS) is a variant of non-invasive neuromodulation, which promises treatment for brain diseases like major depressive disorder. In experiments, long-lasting aftereffects were observed, suggesting that persistent plastic changes are induced. The mechanism underlying the emergence of lasting aftereffects, however, remains elusive. Here we propose a model, which assumes that tDCS triggers a homeostatic response of the network involving growth and decay of synapses. The cortical tissue exposed to tDCS is conceived as a recurrent network of excitatory and inhibitory neurons, with synapses subject to homeostatically regulated structural plasticity. We systematically tested various aspects of stimulation, including electrode size and montage, as well as stimulation intensity and duration. Our results suggest that transcranial stimulation perturbs the homeostatic equilibrium and leads to a pronounced growth response of the network. The stimulated population eventually eliminates excitatory synapses with the unstimulated population, and new synapses among stimulated neurons are grown to form a cell assembly. Strong focal stimulation tends to enhance the connectivity within new cell assemblies, and repetitive stimulation with well-chosen duty cycles can increase the impact of stimulation even further. One long-term goal of our work is to help optimizing the use of tDCS in clinical applications.

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ESTIMATION OF THE LYAPUNOV SPECTRUM FROM ONE-DIMENSIONAL OBSERVATIONS USING NEURAL NETWORKS

International Journal of Computing ◽

10.47839/ijc.2.2.201 ◽

2014 ◽

pp. 30-34

Author(s):

Vladimir Golovko

Keyword(s):

Neural Network ◽

Dynamical System ◽

Neural Networks ◽

Time Series ◽

Lyapunov Spectrum ◽

Network Approach ◽

Neural Network Approach ◽

One Dimensional ◽

The Neural Network ◽

Attractor Dynamics

This paper discusses the neural network approach for computing of Lyapunov spectrum using one dimensional time series from unknown dynamical system. Such an approach is based on the reconstruction of attractor dynamics and applying of multilayer perceptron (MLP) for forecasting the next state of dynamical system from the previous one. It allows for evaluating the Lyapunov spectrum of unknown dynamical system accurately and efficiently only by using one observation. The results of experiments are discussed.

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Functional differences between L- and T-plastin isoforms.

The Journal of Cell Biology ◽

10.1083/jcb.127.6.1995 ◽

1994 ◽

Vol 127 (6) ◽

pp. 1995-2008 ◽

Cited By ~ 64

Author(s):

M Arpin ◽

E Friederich ◽

M Algrain ◽

F Vernel ◽

D Louvard

Keyword(s):

Cell Line ◽

Tissue Specificity ◽

Cell Function ◽

Biological Significance ◽

Epithelial Cell Line ◽

Functional Differences ◽

Cell Biol ◽

Ionic Detergent ◽

A Cell ◽

Cell Type Specific

Fimbrins/plastins are a family of highly conserved actin-bundling proteins. They are present in all eukaryotic cells including yeast, but each isoform displays a remarkable tissue specificity. T-plastin is normally found in epithelial and mesenchymal cells while L-plastin is present in hematopoietic cells. However, L-plastin has been also found in tumor cells of non-hematopoietic origin (Lin, C.-S., R. H. Aebersold, S. B. Kent, M. Varma, and J. Leavitt. 1988. Mol. Cell. Biol. 8:4659-4668; Lin, C.-S., R. H. Aebersold, and J. Leavitt. 1990. Mol. Cell. Biol. 10: 1818-1821). To learn more about the biological significance of their tissue specificity, we have overproduced the T- and L-plastin isoforms in a fibroblast-like cell line, CV-1, and in a polarized epithelial cell line, LLC-PK1. In CV-1 cells, overproduction of T- and L-plastins induces cell rounding and a concomitant reorganization of actin stress fibers into geodesic structures. L-plastin remains associated with microfilaments while T-plastin is almost completely extracted after treatment of the cells with non-ionic detergent. In LLC-PK1 cells, T-plastin induces shape changes in microvilli and remains associated with microvillar actin filaments after detergent extraction while L-plastin has no effect on these structures and is completely extracted. The effect of T-plastin on the organization of microvilli differs from that of villin, another actin-bundling protein. Our experiments indicate that these two isoforms play differing roles in actin filament organization, and do so in a cell type-specific fashion. Thus it is likely that these plastin isoforms play fundamentally different roles in cell function.

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