scholarly journals Whole-ganglion imaging of voltage in the medicinal leech using a double-sided microscope

2017 ◽  
Author(s):  
Yusuke Tomina ◽  
Daniel A. Wagenaar
Keyword(s):  
Membrane Potential ◽  
Sensory Processing ◽  
Action Potentials ◽  
Large Population ◽  
Medicinal Leech ◽  
Simultaneous Recording ◽  
Neuronal Dynamics ◽  
Using Data ◽  
Almost All ◽  
Two Sides

AbstractStudies of neuronal network emergence during sensory processing and motor control are greatly promoted by technologies that allow us to simultaneously record the membrane potential dynamics of a large population of neurons in single cell resolution. To achieve whole-brain recording with the ability to detect both small synaptic potentials and action potentials, we developed a voltage-sensitive dye (VSD) imaging technique based on a double-sided microscope that can image two sides of a nervous system simultaneously. We applied this system to the segmental ganglia of the medicinal leech. Double-sided VSD imaging enabled simultaneous recording of membrane potential events from almost all of the identifiable neurons. Using data obtained from double-sided VSD imaging we analyzed neuronal dynamics in both sensory processing and generation of behavior and constructed functional maps for identification of neurons contributing to these processes.

scholarly journals A double-sided microscope to realize whole-ganglion imaging of membrane potential in the medicinal leech

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Yusuke Tomina ◽  
Daniel A Wagenaar
Keyword(s):  
Membrane Potential ◽  
Sensory Processing ◽  
Action Potentials ◽  
Large Population ◽  
Medicinal Leech ◽  
Simultaneous Recording ◽  
Neuronal Dynamics ◽  
Using Data ◽  
Almost All ◽  
Two Sides

Studies of neuronal network emergence during sensory processing and motor control are greatly facilitated by technologies that allow us to simultaneously record the membrane potential dynamics of a large population of neurons in single cell resolution. To achieve whole-brain recording with the ability to detect both small synaptic potentials and action potentials, we developed a voltage-sensitive dye (VSD) imaging technique based on a double-sided microscope that can image two sides of a nervous system simultaneously. We applied this system to the segmental ganglia of the medicinal leech. Double-sided VSD imaging enabled simultaneous recording of membrane potential events from almost all of the identifiable neurons. Using data obtained from double-sided VSD imaging, we analyzed neuronal dynamics in both sensory processing and generation of behavior and constructed functional maps for identification of neurons contributing to these processes.

scholarly journals Switching in the activity state of an interneuron that controls coordination of the hearts in the medicinal leech (Hirudo medicinalis)

1994 ◽  
Vol 186 (1) ◽  
pp. 157-171 ◽  
Author(s):  
S. Gramoll ◽  
J. Schmidt ◽  
R. L. Calabrese
Keyword(s):  
Membrane Potential ◽  
Action Potentials ◽  
Oscillation Amplitude ◽  
Reversal Potential ◽  
Outward Current ◽  
Medicinal Leech ◽  
Active State ◽  
Membrane Properties ◽  
Inhibitory Input ◽  
Inactive State

The rhythmically active heart interneuron HN(5) in the medicinal leech exhibits two distinct activity states, which have been associated with different coordination states of the two hearts. During the active state, it discharges high-frequency bursts of action potentials interrupted by rhythmic inhibitory input from other interneurons. In the inactive state, the same cell receives rhythmic inhibition but the membrane potential remains subthreshold between these volleys, producing few or no action potentials. We investigated differences in the membrane properties of the cell during the active and inactive states. The membrane potential in the active state oscillates on average between about −56 +/− 6 mV (S.D.) and −45 +/− 7 mV; the mean oscillation amplitude is 11 +/− 4 mV. In the inactive state, the membrane potential oscillates on average between −58 +/− 6 mV and −55 +/− 6 mV with a mean amplitude of 3 +/− 1 mV. The overall conductance of an HN(5) interneuron during the active state is approximately 10 nS lower than that during the inactive state, indicating that an outward current is turned off during the active state or turned on during the inactive state. This outward current is not voltage-dependent in the range −80 mV to −10 mV, as shown in voltage-clamp experiments by a linear current-voltage relationship. The reversal potential of this current is approximately −60 mV, indicating that chloride or potassium ions underlie the current. Using dynamic-clamp, we show that by adding an artificial current with a linear voltage-dependence (leak conductance) to an HN(5) interneuron (conductance 15 nS, reversal potential −60 mV), the cell can be transferred from its active to its inactive state.

New Molecular Scaffolds for Fluorescent Voltage Indicators

2018 ◽  
Author(s):  
Steven Boggess ◽  
Shivaani Gandhi ◽  
Brian Siemons ◽  
Nathaniel Huebsch ◽  
Kevin Healy ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Action Potentials ◽  
Induced Pluripotent Stem Cell ◽  
Molecular Wire ◽  
Voltage Sensing ◽  
Design Synthesis ◽  
Cardiac Action ◽  
Action Potential Waveform ◽  
Induced Pluripotent ◽  
Voltage Sensing Domain

<div> <p>The ability to non-invasively monitor membrane potential dynamics in excitable cells like neurons and cardiomyocytes promises to revolutionize our understanding of the physiology and pathology of the brain and heart. Here, we report the design, synthesis, and application of a new class of fluorescent voltage indicator that makes use of a fluorene-based molecular wire as a voltage sensing domain to provide fast and sensitive measurements of membrane potential in both mammalian neurons and human-derived cardiomyocytes. We show that the best of the new probes, fluorene VoltageFluor 2 (fVF 2) readily reports on action potentials in mammalian neurons, detects perturbations to cardiac action potential waveform in human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes, shows a substantial decrease in phototoxicity compared to existing molecular wire-based indicators, and can monitor cardiac action potentials for extended periods of time. Together, our results demonstrate the generalizability of a molecular wire approach to voltage sensing and highlights the utility of fVF 2 for interrogating membrane potential dynamics.</p> </div>

Risk Analysis for Knowledge Sharing in Tax Payment

2016 ◽  
Vol 6 (1) ◽  
pp. 20-37
Author(s):  
Zahra Kazemi ◽  
Ahmad Jafari Samimi ◽  
Hamed Fazlollahtabar
Keyword(s):  
Knowledge Sharing ◽  
Tax Evasion ◽  
Developed Countries ◽  
Government Expenditures ◽  
Positive Effects ◽  
The People ◽  
Using Data ◽  
Tax Payments ◽  
Almost All ◽  
Tax Payers

One way to finance government expenditures is to collect taxes. Regarding to this financial source compared with other sources positive tax knowledge sharing amongst people or tax payers lead to effective investment. Unlike developing countries in developed countries - that taxes have little effects - almost all government expenditures is financed by taxes. One of the main challenges in the tax system is how to collect taxes due to tax evasion. The main reason is the uncertainty surrounding how government uses the taxes paid by the people. A major factor in the outbreak of the sense of failure to pay taxes, is the discussion and sharing the viewpoint of each other. If there is any positive tax effect prevalence of speech among people motivate them to pay more and if not, paying taxes is impaired. Therefore in order to avoid disorderliness in paying taxes that lead to a reduction in the development growth rate of investing taxes in industry and services sectors procedures should be designed so that taxes spread in speech with more quality. In this article five categories that people share their knowledge about them with each other, have been proposed. Defining risk structure and using data from surveying form the risk values of tax payment the results indicate that sharing tax knowledge amongst people have positive effects on tax payments.

Effects of intracellular potassium and sodium injections on the inhibitory postsynaptic potential

1964 ◽  
Vol 160 (979) ◽  
pp. 181-196 ◽  
Keyword(s):  
Spinal Cord ◽  
Membrane Potential ◽  
Cell Membrane ◽  
Direct Evidence ◽  
Equilibrium Potential ◽  
Ionic Mechanism ◽  
Half Time ◽  
Intracellular Potassium ◽  
Postsynaptic Potential ◽  
Almost All

Two barrels of double microelectrodes have been filled with different salts so that the electrophoretic injection of Na + and K + ions could be investigated in alternating sequence on the same motoneuron in the cat spinal cord. The effects of these injections on the mechanism generating the IPSP were evaluated by determining the equilibrium potential for the IPSP (the E IPSP ), i. e. the membrane potential at which the IPSP is zero. Such determinations have been made every 5 to 10 s after ion injections and have provided the most direct evidence of the ionic mechanism generating the IPSP . Comparison of the Na + and K + ion injections shows that the former injection always displaced the E IPSP much farther in the depolarizing direction and that recovery was much slower, with a half-time of 70 to 120 s, in contrast to about 20 s after the K + injection. In the discussion and evaluation of these results it was postulated that almost all of the displacement of the E IPSP in the depolarizing direction was due to the increased intracellular Cl - concentration, the (Cl - ) i . Under normal conditions a high (Cl - ) i declines by diffusional exchange across the cell membrane with a half-time of about 20 s, but this decline is much slower when the internal potassium is depleted. An explanation of this difference will be given in the following paper.

scholarly journals Urban Accounting and Welfare

2013 ◽  
Vol 103 (6) ◽  
pp. 2296-2327 ◽  
Author(s):  
Klaus Desmet ◽  
Esteban Rossi-Hansberg
Keyword(s):  
Large Population ◽  
The United States ◽  
Welfare Effects ◽  
City Size ◽  
Negative Effects ◽  
The Us ◽  
City Size Distribution ◽  
Using Data ◽  
Main Components ◽  
The City

We use a simple theory of a system of cities to decompose the determinants of the city size distribution into three main components: efficiency, amenities, and frictions. Higher efficiency and better amenities lead to larger cities but also to greater frictions through congestion and other negative effects of agglomeration. Using data on MSAs in the United States, we estimate these city characteristics. Eliminating variation in any of them leads to large population reallocations, but modest welfare effects. We apply the same methodology to Chinese cities and find welfare effects that are many times larger than those in the US. (JEL H71, O18, P25, R11, R23, R41)

scholarly journals STATISTICAL STUDIES ON PROTEIN POLYMORPHISM IN NATURAL POPULATIONS II. GENE DIFFERENTIATION BETWEEN POPULATIONS

Genetics ◽  
1978 ◽  
Vol 88 (2) ◽  
pp. 367-390
Author(s):  
Ranajit Chakraborty ◽  
Paul A Fuerst ◽  
Masatoshi Nei
Keyword(s):  
Genetic Differentiation ◽  
Natural Populations ◽  
Drift Theory ◽  
Alternative Hypotheses ◽  
Mean And Variance ◽  
Statistical Studies ◽  
Different Populations ◽  
Using Data ◽  
Almost All ◽  
Good Agreement

ABSTRACT With the aim of testing the validity of the mutation-drift hypothesis, we examined the pattern of genetic differentiation between populations by using data from Drosophila, fishes, reptiles, and mammals. The observed relationship between genetic identity and correlation of heterozygosities of different populations or species was generally in good agreement with the theoretical expectations from the mutation-drift theory, when the variation in mutation rate among loci was taken into account. In some species of Drosophila, however, the correlation was unduly high. The relationship between the mean and variance of genetic distance was also in good agreement with the theoretical prediction in almost all organisms. We noted that both the distribution of heterozygosity within species and the pattern of genetic differentiation between species can be explained by the same set of genetic parameters in each group of organisms. Alternative hypotheses for explaining these observations are discussed.

scholarly journals Predicting heart ailment in patients with varying number of features using data mining techniques

2019 ◽  
Vol 8 (1) ◽  
pp. 56
Author(s):  
T R Stella Mary ◽  
Shoney Sebastian
Keyword(s):  
Data Mining ◽  
Heart Disease ◽  
Random Forest ◽  
Naive Bayes ◽  
Heart Diseases ◽  
Naïve Bayes ◽  
Bayes Classifier ◽  
Data Mining Techniques ◽  
Using Data ◽  
Almost All

<span>Data mining can be defined as a process of extracting unknown, verifiable and possibly helpful data from information. Among the various ailments, heart ailment is one of the primary reason behind death of individuals around the globe, hence in order to curb this, a detailed analysis is done using Data Mining. Many a times we limit ourselves with minimal attributes that are required to predict a patient with heart disease. By doing so we are missing on a lot of important attributes that are main causes for heart diseases. Hence, this research aims at considering almost all the important features affecting heart disease and performs the analysis step by step with minimal to maximum set of attributes using Data Mining techniques to predict heart ailments. The various classification methods used are Naïve Bayes classifier, Random Forest and Random Tree which are applied on three datasets with different number of attributes but with a common class label. From the analysis performed, it shows that there is a gradual increase in prediction accuracies with the increase in the attributes irrespective of the classifiers used and Naïve Bayes and Random Forest algorithms comparatively outperforms with these sets of data.</span>

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