The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
David W Tank - One of the best experts on this subject based on the ideXlab platform.
-
Membrane Potential dynamics of grid cells
Nature, 2013Co-Authors: Cristina Domnisoru, Amina A Kinkhabwala, David W TankAbstract:During navigation, grid cells increase their spike rates in firing fields arranged on a markedly regular triangular lattice, whereas their spike timing is often modulated by theta oscillations. Oscillatory interference models of grid cells predict theta amplitude modulations of Membrane Potential during firing field traversals, whereas competing attractor network models predict slow depolarizing ramps. Here, using in vivo whole-cell recordings, we tested these models by directly measuring grid cell intracellular Potentials in mice running along linear tracks in virtual reality. Grid cells had large and reproducible ramps of Membrane Potential depolarization that were the characteristic signature tightly correlated with firing fields. Grid cells also demonstrated intracellular theta oscillations that influenced their spike timing. However, the properties of theta amplitude modulations were not consistent with the view that they determine firing field locations. Our results support cellular and network mechanisms in which grid fields are produced by slow ramps, as in attractor models, whereas theta oscillations control spike timing. Intracellular Membrane Potential changes are measured directly in mouse grid cells during navigation along linear tracks in virtual reality; the recordings reveal that slow ramps of depolarization are the sub-threshold signatures of firing fields, as in attractor network models of grid cells, whereas theta oscillations pace action Potential timing. The grid cells in the medial temporal lobe, the part of the brain that deals with higher level functions including memory, fire in a periodic lattice-like fashion to aid navigation, but it is still not clear how these grid-like firing patterns emerge. Here, David Tank and colleagues directly measure voltage changes and intracellular dynamics in these cells in mice running along linear tracks in virtual reality. They find that grid-firing fields are produced by slow ramps of depolarization, and that grid cells also exhibit intracellular theta oscillations that influenced their spike timing. The data are most consistent with models in which the grids arise from attractor dynamics and theta oscillations control the spike timing of grid cells.
-
Membrane Potential dynamics of grid cells
Nature, 2013Co-Authors: Cristina Domnisoru, Amina A Kinkhabwala, David W TankAbstract:During navigation, grid cells increase their spike rates in firing fields arranged on a markedly regular triangular lattice, whereas their spike timing is often modulated by theta oscillations. Oscillatory interference models of grid cells predict theta amplitude modulations of Membrane Potential during firing field traversals, whereas competing attractor network models predict slow depolarizing ramps. Here, using in vivo whole-cell recordings, we tested these models by directly measuring grid cell intracellular Potentials in mice running along linear tracks in virtual reality. Grid cells had large and reproducible ramps of Membrane Potential depolarization that were the characteristic signature tightly correlated with firing fields. Grid cells also demonstrated intracellular theta oscillations that influenced their spike timing. However, the properties of theta amplitude modulations were not consistent with the view that they determine firing field locations. Our results support cellular and network mechanisms in which grid fields are produced by slow ramps, as in attractor models, whereas theta oscillations control spike timing.
Christine Payne - One of the best experts on this subject based on the ideXlab platform.
-
A model for controlling the resting Membrane Potential of cells using nanoparticles
53rd IEEE Conference on Decision and Control, 2014Co-Authors: Shayok Mukhopadhyay, Fumin Zhang, Emilie Warren, Christine PayneAbstract:This paper presents a novel dynamical system model for the resting Membrane Potential of cells. The novelty of this work is that the model allows parameters related to permeabilities of ion channels to be controlled so the resting Membrane Potential reaches a desired value. We are then able to explain the decreased polarity across the cell Membrane when nanoparticles are introduced in the vicinity of a cell. The effect of varying these parameters on the resting Membrane Potential of a cell is investigated. The proposed model allows simulation of the behaviors of the resting Membrane Potential that matches experimental data.
Cristina Domnisoru - One of the best experts on this subject based on the ideXlab platform.
-
Membrane Potential dynamics of grid cells
Nature, 2013Co-Authors: Cristina Domnisoru, Amina A Kinkhabwala, David W TankAbstract:During navigation, grid cells increase their spike rates in firing fields arranged on a markedly regular triangular lattice, whereas their spike timing is often modulated by theta oscillations. Oscillatory interference models of grid cells predict theta amplitude modulations of Membrane Potential during firing field traversals, whereas competing attractor network models predict slow depolarizing ramps. Here, using in vivo whole-cell recordings, we tested these models by directly measuring grid cell intracellular Potentials in mice running along linear tracks in virtual reality. Grid cells had large and reproducible ramps of Membrane Potential depolarization that were the characteristic signature tightly correlated with firing fields. Grid cells also demonstrated intracellular theta oscillations that influenced their spike timing. However, the properties of theta amplitude modulations were not consistent with the view that they determine firing field locations. Our results support cellular and network mechanisms in which grid fields are produced by slow ramps, as in attractor models, whereas theta oscillations control spike timing. Intracellular Membrane Potential changes are measured directly in mouse grid cells during navigation along linear tracks in virtual reality; the recordings reveal that slow ramps of depolarization are the sub-threshold signatures of firing fields, as in attractor network models of grid cells, whereas theta oscillations pace action Potential timing. The grid cells in the medial temporal lobe, the part of the brain that deals with higher level functions including memory, fire in a periodic lattice-like fashion to aid navigation, but it is still not clear how these grid-like firing patterns emerge. Here, David Tank and colleagues directly measure voltage changes and intracellular dynamics in these cells in mice running along linear tracks in virtual reality. They find that grid-firing fields are produced by slow ramps of depolarization, and that grid cells also exhibit intracellular theta oscillations that influenced their spike timing. The data are most consistent with models in which the grids arise from attractor dynamics and theta oscillations control the spike timing of grid cells.
-
Membrane Potential dynamics of grid cells
Nature, 2013Co-Authors: Cristina Domnisoru, Amina A Kinkhabwala, David W TankAbstract:During navigation, grid cells increase their spike rates in firing fields arranged on a markedly regular triangular lattice, whereas their spike timing is often modulated by theta oscillations. Oscillatory interference models of grid cells predict theta amplitude modulations of Membrane Potential during firing field traversals, whereas competing attractor network models predict slow depolarizing ramps. Here, using in vivo whole-cell recordings, we tested these models by directly measuring grid cell intracellular Potentials in mice running along linear tracks in virtual reality. Grid cells had large and reproducible ramps of Membrane Potential depolarization that were the characteristic signature tightly correlated with firing fields. Grid cells also demonstrated intracellular theta oscillations that influenced their spike timing. However, the properties of theta amplitude modulations were not consistent with the view that they determine firing field locations. Our results support cellular and network mechanisms in which grid fields are produced by slow ramps, as in attractor models, whereas theta oscillations control spike timing.
Michael P Murphy - One of the best experts on this subject based on the ideXlab platform.
-
changes in mitochondrial Membrane Potential during staurosporine induced apoptosis in jurkat cells
FEBS Letters, 2000Co-Authors: Jared L Scarlett, Philip W Sheard, Gillian Hughes, Elizabeth C Ledgerwood, Hunghai Ku, Michael P MurphyAbstract:Cytochrome c release from mitochondria is central to apoptosis, but the events leading up to it are disputed. The mitochondrial Membrane Potential has been reported to decrease, increase or remain unchanged during cytochrome c release. We measured mitochondrial Membrane Potential in Jurkat cells undergoing apoptosis by the uptake of the radiolabelled lipophilic cation TPMP, enabling small changes in Potential to be determined. The ATP/ADP ratio, mitochondrial and cell volumes, plasma Membrane Potential and the mitochondrial Membrane Potential in permeabilised cells were also measured. Before cytochrome c release the mitochondrial Membrane Potential increased, followed by a decrease in Potential associated with mitochondrial swelling and the release of cytochrome c and DDP-1, an interMembrane space house keeping protein. Mitochondrial swelling and cytochrome c release were both blocked by bongkrekic acid, an inhibitor of the permeability transition. We conclude that during apoptosis mitochondria undergo an initial priming phase associated with hyperpolarisation which leads to an effector phase, during which mitochondria swell and release cytochrome c.
Dong-soon Im - One of the best experts on this subject based on the ideXlab platform.
-
Wuweizisu C from Schisandra chinensis decreases Membrane Potential in C6 glioma cells
Acta Pharmacologica Sinica, 2008Co-Authors: Young-whan Choi, Santosh J. Sacket, Ji-yeong Jo, Woo-jung Shin, Dong-soon ImAbstract:Aim: To study the effects of dibenzocyclooctadiene lignans isolated from Schisandra chinensis , such as wuweizisu C, gomisin N, gomisin A, and schisandrin, on the Membrane Potential in C6 glioma cells. Methods: The Membrane Potential was estimated by measuring the fluorescence change in DiBAC-loaded glioma cells. Results: Wuweizisu C decreased the Membrane Potential in a concentration-dependent manner. Gomisin N and gomisin A, however, showed differential modulation and no change was induced by schisandrin or dimethyl-4,4′-dimethoxy-5,6,5′,6′-dimethylene dioxybipheny 1-2,2′-dicarboxylate, a synthetic drug derived from dibenzocyclooctadiene lignans. We found no involvement of G_i/o proteins, phospholipase C, and extracellular Na^+ on the wuweizisu C-induced decrease of the Membrane Potential. Wuweizisu C by itself did not change the intracellular Ca^2+ [Ca^2+]_i concentration, but decreased the ATP-indu-ced Ca^2+ increase in C6 glioma cells. The 4 lignans at all concentrations used in this study did not induce any effect on cell viability. Furthermore, we found a similar decrease of the Membrane Potential by wuweizisu C in PC12 neuronal cells. Conclusion: Our results suggest that the decrease in the Membrane Potential and the modulation of [Ca^2+]_i concentration by wuweizisu C could be important action mechanisms of wuweizisu C.
-
Increase of Membrane Potential by Ginsenosides in Prostate Cancer and Glioma cells
Journal of Ginseng Research, 2006Co-Authors: Young-jin Im, Santosh J. Sacket, Sung-ryong Ko, Dong-soon ImAbstract:Ginseng has an anti-cancer effect in several cancer models. As a mechanism study of ginsenoside-induced growth inhibition in cancer cells, we measured change of Membrane Potential in prostate cancer and glioma cells by ginsenosides, active constituents of ginseng. Membrane Potential was estimated by measuring fluorescence change of DiBAC-loaded cells. Among 11 ginsenosides tested, ginsenosides Rb₂, Rg₃, and Rh₂ increased significantly and robustly the Membrane Potential in a concentration-dependent manner in prostate cancer and glioma cells. Ginsenosides Rc, Ro, and Rb₁ slightly increased Membrane Potential. The ginsenoside-induced Membrane Potential increase was not affected by treatment with pertussis toxin or U73122. The ginsenoside-induced Membrane Potential increase was not diminished in Na?-free or HCO₃?-free media. Furthermore, the ginsenoside-induced increase of Membrane Potential was not changed by EIPA (5-(N-ethyl-N-isopropyl)-amiloride), SITS (4-acetoamido-4’-isothiocyanostilbene-2,2’-disulfonic acid), and omeprazole. In summary, ginsenosides Rb₂, Rg₃, and Rh₂ increased Membrane Potential in prostate cancer and glioma cells in a GPCR-independent and Na? independent manner.
