Visualization of membrane potential changes induced by oscillating electric fields (Conference Presentation)

2020 ◽  
Author(s):  
Allen Kiester ◽  
Zach Coker ◽  
Bennett Ibey ◽  
Joel Bixler
Keyword(s):  
Membrane Potential ◽  
Electric Fields

scholarly journals Feasibility analysis of semiconductor voltage nanosensors for neuronal membrane potential sensing

2019 ◽  
Author(s):  
Anastasia Ludwig ◽  
Pablo Serna ◽  
Lion Morgenstein ◽  
Gaoling Yang ◽  
Omri Bar-Elli ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Electric Fields ◽  
Stark Effect ◽  
High Sensitivity ◽  
Time Lapse ◽  
Neuronal Membrane ◽  
Attractive Alternative ◽  
Wide Field ◽  
Particle Level ◽  
Semiconductor Voltage

AbstractIn the last decade, optical imaging methods have significantly improved our understanding of the information processing principles in the brain. Although many promising tools have been designed, sensors of membrane potential are lagging behind the rest. Semiconductor nanoparticles are an attractive alternative to classical voltage indicators, such as voltage-sensitive dyes and proteins. Such nanoparticles exhibit high sensitivity to external electric fields via the quantum-confined Stark effect. Here we report the development of lipid-coated semiconductor voltage-sensitive nanorods (vsNRs) that self-insert into the neuronal membrane. We describe a workflow to detect and process the photoluminescent signal of vsNRs after wide-field time-lapse recordings. We also present data indicating that vsNRs are feasible for sensing membrane potential in neurons at a single-particle level. This shows the potential of vsNRs for detection of neuronal activity with unprecedentedly high spatial and temporal resolution.

Mapping membrane-potential perturbations of chromaffin cells exposed to electric fields

2002 ◽  
Vol 30 (4) ◽  
pp. 1516-1524 ◽  
Author(s):  
N. Hassan ◽  
I. Chatterjee ◽  
N.G. Publicover ◽  
G.L. Craviso
Keyword(s):  
Membrane Potential ◽  
Electric Fields ◽  
Chromaffin Cells

scholarly journals Motility of cultured fish epidermal cells in the presence and absence of direct current electric fields.

1986 ◽  
Vol 102 (4) ◽  
pp. 1384-1399 ◽  
Author(s):  
M S Cooper ◽  
M Schliwa
Keyword(s):  
Membrane Potential ◽  
Electric Field ◽  
Electric Fields ◽  
Direct Current ◽  
Epidermal Cells ◽  
Resting Membrane Potential ◽  
Cell Clusters ◽  
Cell Locomotion ◽  
Presence And Absence ◽  
Dc Electric Fields

The motile behavior and cytoskeletal structures of fish epidermal cells (keratocytes) in the presence and absence of direct current (DC) electric fields were examined. These cells spontaneously show highly directional locomotion in culture, migrating at rates of up to 1 micron/s. When DC electric fields between 0.5 and 15 V/cm are applied, single epidermal cells as well as cell clusters and cell sheets migrate towards the cathode. Cell clusters and sheets break apart into single migratory cells in the upper range of these field strengths. Cell shape and morphology are unaltered when the keratocytes are guided by an electric field. Neither the spontaneous locomotion nor the electrically guided motility were found to be microtubule dependent. 1 mM La3+, 10 mM Co2+, 50 microM verapamil, and 50 microM nitrendipine (calcium channel antagonists) reversibly inhibited lamellipod formation and cell locomotion in both spontaneously migrating and electrically guided cells. Ciba-Geigy Product 28392, which stimulates the opening of calcium channels, and is a competitive inhibitor of nitrendipine, has no effect on the locomotion of keratocytes. Cell motility was also unaffected by hyperpolarizing and depolarizing (low and high K+) media. It is argued that while a tissue cell may accommodate changes in resting membrane potential without becoming more or less motile, the cell may not be able to counterbalance the effects of depolarization and hyperpolarization simultaneously. In this context, a gradient of membrane potential, which is induced by an external DC electric field, will serve as a persistent stimulus for cell locomotion.

scholarly journals Analysis and extension of exact mean-field theory with dynamic synaptic currents

2021 ◽  
Author(s):  
Giulio Ruffini
Keyword(s):  
Field Theory ◽  
Membrane Potential ◽  
Firing Rate ◽  
Electric Fields ◽  
Mean Field Theory ◽  
Mean Field ◽  
Period Doubling ◽  
Population Connectivity ◽  
Sigmoid Function ◽  
Synaptic Currents

Neural mass models such as the Jansen-Rit system provide a practical framework for representing and interpreting electrophysiological activity (1-6) in both local and global brain models (7). However, they are only partly derived from first principles. While the post-synaptic potential dynamics in NMM are inferred from data and can be grounded on diffusion physics (8-10), Freeman's "wave to pulse" sigmoid function (11-13) is used to transduce mean population membrane potential into firing rate rests on a weaker theoretical standing. On the other hand, Montbrio et al (14, 15) derive an exact mean-field theory from a quadratic integrate and fire neuron model under some simplifying assumptions (MPR), connecting microscale neural mechanisms and meso/macroscopic phenomena. The MPR model can be seen to replace Freeman's sigmoid function with a pair of differential equations for the mean membrane potential and firing rate variables, providing a mechanistic interpretation of NMM semi-empirical sigmoid parameters. In doing so, it sheds light on the mechanisms behind enhanced network response to weak but uniform perturbations: in the exact mean-field theory, intrinsic population connectivity modulates the steady-state firing rate transfer function in a monotonic manner, with increasing self-connectivity leading to higher firing rates. This provides a plausible mechanism for the enhanced response of densely connected networks to weak, uniform inputs such as the electric fields produced by non-invasive brain stimulation. Finally, we complete the MPR model by adding the equations for delayed post-synaptic currents, bringing together the MPR and NMM formalisms into a unified exact mean-field theory (NMM2) displaying rich dynamical features. As an example, we analyze the dynamics of a single population model, and a model of two coupled populations with a simple excitation-inhibition (E-I) architecture, showing it displays rich dynamics with limit cycles, period doubling, bursting behavior, and enhanced sensitivity to external inputs.

Ca45 and Sr89 movements with contraction of depolarized smooth muscle

1962 ◽  
Vol 203 (5) ◽  
pp. 860-866 ◽  
Author(s):  
Nick Sperelakis
Keyword(s):  
Smooth Muscle ◽  
Membrane Potential ◽  
Electric Fields ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Circular Layer ◽  
Washout Curves ◽  
Depolarized Smooth Muscle

Previous findings showed that contractions of depolarized muscle bypass excitation-contraction coupling and that Sr replaces Ca in the contractile machinery but not in coupling. Polarized and K-depolarized thin strips of circular layer of cat intestine were subjected to electric fields. Washout curves for Ca45 from resting muscles were composed of two exponentials with half-times of 8 min and 60 min. Ca influxes were increased in contracting muscles in both polarized and depolarized conditions. Resting influx was greater in K-Tyrode than in normal Tyrode's solution. With Sr the ratio of influxes of stimulated to resting polarized muscles was not significantly different from 1.0; contractions of polarized muscles were weak due to uncoupling. Uncoupling produced by 20 mm/liter Mg resulted in a ratio of Ca influxes of stimulated to resting polarized muscles not significantly different from 1.0. It is suggested that Ca entrance is not the sole coupling event and that increased Ca or Sr influx is more closely related to contraction than to changes in membrane potential.

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