Electrical stimulation of cardiac tissue: a bidomain model with active membrane properties

1994 ◽  
Vol 41 (3) ◽  
pp. 232-240 ◽  
Author(s):  
B.J. Roth ◽  
J.P. Wikswo
Keyword(s):  
Electrical Stimulation ◽  
Cardiac Tissue ◽  
Membrane Properties ◽  
Bidomain Model ◽  
Active Membrane ◽  
Stimulation Of

Second-Order Vestibular Neurons Form Separate Populations With Different Membrane and Discharge Properties

2004 ◽  
Vol 92 (2) ◽  
pp. 845-861 ◽  
Author(s):  
H. Straka ◽  
M. Beraneck ◽  
M. Rohregger ◽  
L. E. Moore ◽  
P.-P. Vidal ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Second Order ◽  
Membrane Properties ◽  
Discharge Pattern ◽  
Response Dynamics ◽  
Vestibular Neurons ◽  
Positive Current ◽  
Current Steps ◽  
Passive Membrane Properties ◽  
Stimulation Of

Membrane and discharge properties were determined in second-order vestibular neurons (2°VN) in the isolated brain of grass frogs. 2°VN were identified by monosynaptic excitatory postsynaptic potentials after separate electrical stimulation of the utricular nerve, the lagenar nerve, or individual semicircular canal nerves. 2°VN were classified as vestibulo-ocular or -spinal neurons by the presence of antidromic spikes evoked by electrical stimulation of the spinal cord or the oculomotor nuclei. Differences in passive membrane properties, spike shape, and discharge pattern in response to current steps and ramp-like currents allowed a differentiation of frog 2°VN into two separate, nonoverlapping types of vestibular neurons. A larger subgroup of 2°VN (78%) was characterized by brief, high-frequency bursts of up to five spikes and the absence of a subsequent continuous discharge in response to positive current steps. In contrast, the smaller subgroup of 2°VN (22%) exhibited a continuous discharge with moderate adaptation in response to positive current steps. The differences in the evoked spike discharge pattern were paralleled by differences in passive membrane properties and spike shapes. Despite these differences in membrane properties, both types, i.e., phasic and tonic 2°VN, occupied similar anatomical locations and displayed similar afferent and efferent connectivities. Differences in response dynamics of the two types of 2°VN match those of their pre- and postsynaptic neurons. The existence of distinct populations of 2°VN that differ in response dynamics but not in the spatial organization of their afferent inputs and efferent connectivity to motor targets suggests that frog 2°VN form one part of parallel vestibulomotor pathways.

Search for the optimal mode of electrical stimulation of cardiac tissue

1998 ◽  
Vol 34 (6) ◽  
pp. 870-878
Author(s):  
G. Dzemida ◽  
R. Veteikis ◽  
A. Krishchyukaitis
Keyword(s):  
Electrical Stimulation ◽  
Cardiac Tissue ◽  
Optimal Mode ◽  
Stimulation Of

The laws of electrical stimulation of cardiac tissue

1996 ◽  
Vol 84 (3) ◽  
pp. 355-365 ◽  
Author(s):  
W.A. Tacker ◽  
L.A. Geddes
Keyword(s):  
Electrical Stimulation ◽  
Cardiac Tissue ◽  
Stimulation Of

Computer simulations of successful defibrillation in decoupled and non-uniform cardiac tissue

EP Europace ◽  
2005 ◽  
Vol 7 (s2) ◽  
pp. S166-S177 ◽  
Author(s):  
N. H. L. Kuijpers ◽  
R. H. Keldermann ◽  
T. Arts ◽  
P. A. J. Hilbers
Keyword(s):  
Electric Fields ◽  
Cardiac Tissue ◽  
Spiral Waves ◽  
Electrode Polarization ◽  
Field Stimulation ◽  
Bidomain Model ◽  
Active Membrane ◽  
External Domain ◽  
Virtual Electrodes ◽  
Homogeneous Tissue

Abstract Aim The aim of the present study is to investigate the origin and effect of virtual electrode polarization in uniform, decoupled and non-uniform cardiac tissue during field stimulation. Methods A discrete bidomain model with active membrane behaviour was used to simulate normal cardiac tissue as well as cardiac tissue that is decoupled due to fibrosis and gap junction remodelling. Various uniform and non-uniform electric fields were applied to the external domain of uniform, decoupled and non-uniform resting cardiac tissue as well as cardiac tissue in which spiral waves were induced. Results Field stimulation applied on non-uniform tissue results in more virtual electrodes compared with uniform tissue. The spiral waves were terminated in decoupled tissue, but not in uniform, homogeneous tissue. By gradually increasing local differences in intracellular conductivities, the amount and spread of virtual electrodes increased and the spiral waves were terminated. Conclusion Fast depolarization of the tissue after field stimulation may be explained by intracellular decoupling and spatial heterogeneity present in normal and pathological cardiac tissue. We demonstrated that termination of spiral waves by means of field stimulation can be achieved when the tissue is modelled as a non-uniform, anisotropic bidomain with active membrane behaviour.

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