scholarly journals Ih interacts with somato-dendritic structure to determine frequency response to weak alternating electric field stimulation

2018 ◽  
Vol 119 (3) ◽  
pp. 1029-1036 ◽  
Author(s):  
Enrique H. S. Toloza ◽  
Ehsan Negahbani ◽  
Flavio Fröhlich
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Cellular Response ◽  
Current Injection ◽  
Field Stimulation ◽  
Electric Field Stimulation ◽  
Cation Current ◽  
Network Oscillations ◽  
Alternating Electric Field

Transcranial current stimulation (tCS) modulates brain dynamics using weak electric fields. Given the pathological changes in brain network oscillations in neurological and psychiatric illnesses, using alternating electric field waveforms that engage rhythmic activity has been proposed as a targeted, network-level treatment approach. Previous studies have investigated the effects of electric fields at the neuronal level. However, the biophysical basis of the cellular response to electric fields has remained limited. Here, we characterized the frequency-dependent response of different compartments in a layer V pyramidal neuron to exogenous electric fields to dissect the relative contributions of voltage-gated ion channels and neuronal morphology. Hyperpolarization-activated cation current (Ih) in the distal dendrites was the primary ionic mechanism shaping the model’s response to electric field stimulation and caused subthreshold resonance in the tuft at 20 ± 4 Hz. In contrast, subthreshold Ih-mediated resonance in response to local sinusoidal current injection was present in all model compartments at 11 ± 2 Hz. The frequencies of both resonance responses were modulated by Ih conductance density. We found that the difference in resonance frequency between the two stimulation types can be explained by the fact that exogenous electric fields simultaneously polarize the membrane potentials at the distal ends of the neuron (relative to field direction) in opposite directions. Our results highlight the role of Ih in shaping the cellular response to electric field stimulation and suggest that the common model of tCS as a weak somatic current injection fails to capture the cellular effects of electric field stimulation. NEW & NOTEWORTHY Modulation of cortical oscillation by brain stimulation serves as a tool to understand the causal role of network oscillations in behavior and is a potential treatment modality that engages impaired network oscillations in disorders of the central nervous system. To develop targeted stimulation paradigms, cellular-level effects must be understood. We demonstrate that hyperpolarization-activated cation current (Ih) and cell morphology cooperatively shape the response to applied alternating electric fields.

scholarly journals Electric field mediated fibronectin-hydroxyapatite interaction: A molecular insight

2020 ◽  
Author(s):  
Subhadip Basu ◽  
Biswajit Gorai ◽  
Bikramjit Basu ◽  
Prabal K. Maiti
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Protein Adsorption ◽  
Structural Integrity ◽  
Critical Role ◽  
Field Stimulation ◽  
Electric Field Stimulation ◽  
Cell Material ◽  
Material Interaction

AbstractIn experimental research driven biomaterials science, the influence of different material properties (elastic stiffness, surface energy, etc.), and to a relatively lesser extent, the biophysical stimulation (electric/magnetic) on the cell-material interaction has been extensively investigated. Considering the central importance of the protein adsorption on cell-material interaction, the role of physiochemical factors on the protein adsorption is also probed. Despite its significance, the quantitative analysis of many such aspects remains largely unexplored in biomaterials science. In recent studies, the critical role of electric field stimulation towards modulation of cell functionality on implantable biomaterials has been experimentally demonstrated. Given this background, we investigated the influence of external electric field stimulation (upto 1.00 V/nm) on fibronectin (FN) adsorption on hydroxyapatite, HA (100) surface at 300K using all-atom MD simulation method. Fibronectin adsorption was found to be governed by the attractive electrostatic interaction, which changed with the electric field strength. Non-monotonous changes in structural integrity of fibronectin were recorded with the change in field strength and direction. This can be attributed to the spatial rearrangement of local charges and global structural changes of the protein. The dipole moment vectors of fibronectin, water and HA quantitatively exhibited similar pattern of orienting themselves parallel to the field direction, with field strength dependent increase in their magnitudes. No significant change has been recorded for radial distribution function of water surrounding fibronectin. Field dependent variation in the salt bridge nets and number of hydrogen bonds between fibronectin and hydroxyapatite were also examined. One of the important results in the context of the cell-material interaction is that the RGD sequence of FN was exposed to solvent side, when the field was applied along a direction outward perpendicular to HA (001) surface. Summarizing, the present study provides quantitative insights into the influence of electric field stimulation on biomolecular interactions involved in fibronectin adsorption on hydroxyapatite surface.

scholarly journals Electric field stimulation for tissue engineering applications

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Christina N. M. Ryan ◽  
Meletios N. Doulgkeroglou ◽  
Dimitrios I. Zeugolis
Keyword(s):  
Tissue Engineering ◽  
Wound Healing ◽  
Electric Field ◽  
Electric Fields ◽  
Cell Types ◽  
Field Stimulation ◽  
Electric Field Stimulation ◽  
Physiological Processes ◽  
Different Cell Types

AbstractElectric fields are involved in numerous physiological processes, including directional embryonic development and wound healing following injury. To study these processes in vitro and/or to harness electric field stimulation as a biophysical environmental cue for organised tissue engineering strategies various electric field stimulation systems have been developed. These systems are overall similar in design and have been shown to influence morphology, orientation, migration and phenotype of several different cell types. This review discusses different electric field stimulation setups and their effect on cell response.

Role of cortical cell type and neuronal morphology in electric field stimulation

2008 ◽  
Vol 1 (3) ◽  
pp. 247-248 ◽  
Author(s):  
T. Radman ◽  
R. Ramos ◽  
J.C. Brumberg ◽  
M. Bikson ◽  
J.C. Brumberg
Keyword(s):  
Electric Field ◽  
Cortical Cell ◽  
Neuronal Morphology ◽  
Field Stimulation ◽  
Cell Type ◽  
Electric Field Stimulation

scholarly journals Elucidating the Influence of Electric Fields toward CO2 Activation on YSZ (111)

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 271
Author(s):  
Nisa Ulumuddin ◽  
Fanglin Che ◽  
Jung-Il Yang ◽  
Su Ha ◽  
Jean-Sabin McEwen
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Heterogeneous Catalysts ◽  
Co2 Reduction ◽  
Total Density ◽  
Reverse Water Gas Shift ◽  
High Thermodynamic Stability ◽  
Shift Reaction ◽  
Water Gas

Despite its high thermodynamic stability, the presence of a negative electric field is known to facilitate the activation of CO2 through electrostatic effects. To utilize electric fields for a reverse water gas shift reaction, it is critical to elucidate the role of an electric field on a catalyst surface toward activating a CO2 molecule. We conduct a first-principles study to gain an atomic and electronic description of adsorbed CO2 on YSZ (111) surfaces when external electric fields of +1 V/Å, 0 V/Å, and −1 V/Å are applied. We find that the application of an external electric field generally destabilizes oxide bonds, where the direction of the field affects the location of the most favorable oxygen vacancy. The direction of the field also drastically impacts how CO2 adsorbs on the surface. CO2 is bound by physisorption when a +1 V/Å field is applied, a similar interaction as to how it is adsorbed in the absence of a field. This interaction changes to chemisorption when the surface is exposed to a −1 V/Å field value, resulting in the formation of a CO3− complex. The strong interaction is reflected through a direct charge transfer and an orbital splitting within the Olatticep-states. While CO2 remains physisorbed when a +1 V/Å field value is applied, our total density of states analysis indicates that a positive field pulls the charge away from the adsorbate, resulting in a shift of its bonding and antibonding peaks to higher energies, allowing a stronger interaction with YSZ (111). Ultimately, the effect of an electric field toward CO2 adsorption is not negligible, and there is potential in utilizing electric fields to favor the thermodynamics of CO2 reduction on heterogeneous catalysts.

Electric Field Stimulation of Delayed Fluorescence in Dry Films of Chloroplasts and Subchloroplast Particles Enriched in PSII

1979 ◽  
Vol 174 (2) ◽  
pp. 85-91 ◽  
Author(s):  
T.V. Ortoidze ◽  
Galina P. Borisevitch ◽  
P.S. Venediktov ◽  
A.A. Kononenko ◽  
D.N. Matorin ◽  
...  
Keyword(s):  
Electric Field ◽  
Delayed Fluorescence ◽  
Field Stimulation ◽  
Electric Field Stimulation ◽  
Stimulation Of

scholarly journals Electric potential differences across auroral generator interfaces

2013 ◽  
Vol 31 (2) ◽  
pp. 251-261 ◽  
Author(s):  
J. De Keyser ◽  
M. Echim
Keyword(s):  
Electric Field ◽  
High Altitude ◽  
Electric Fields ◽  
Electric Potential ◽  
Equilibrium Configuration ◽  
Potential Difference ◽  
Field Profile ◽  
Electric Potential Difference ◽  
Electric Field Profile

Abstract. Strong localized high-altitude auroral electric fields, such as those observed by Cluster, are often associated with magnetospheric interfaces. The type of high-altitude electric field profile (monopolar, bipolar, or more complicated) depends on the properties of the plasmas on either side of the interface, as well as on the total electric potential difference across the structure. The present paper explores the role of this cross-field electric potential difference in the situation where the interface is a tangential discontinuity. A self-consistent Vlasov description is used to determine the equilibrium configuration for different values of the transverse potential difference. A major observation is that there exist limits to the potential difference, beyond which no equilibrium configuration of the interface can be sustained. It is further demonstrated how the plasma densities and temperatures affect the type of electric field profile in the transition, with monopolar electric fields appearing primarily when the temperature contrast is large. These findings strongly support the observed association of monopolar fields with the plasma sheet boundary. The role of shear flow tangent to the interface is also examined.

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