Onset of polyspike complexes in a mean-field model of human electroencephalography and its application to absence epilepsy

Author(s):  
Frank Marten ◽  
Serafim Rodrigues ◽  
Oscar Benjamin ◽  
Mark P Richardson ◽  
John R Terry

In this paper, we introduce a modification of a mean-field model used to describe the brain's electrical activity as recorded via electroencephalography (EEG). The focus of the present study is to understand the mechanisms giving rise to the dynamics observed during absence epilepsy, one of the classical generalized syndromes. A systematic study of the data from a number of different subjects with absence epilepsy demonstrates a wide variety of dynamical phenomena in the recorded EEG. In addition to the classical spike and wave activity, there may be polyspike and wave, wave spike or even no discernible spike–wave onset during seizure events. The model we introduce is able to capture all of these different phenomena and we describe the bifurcations giving rise to these different types of seizure activity. We argue that such a model may provide a useful clinical tool for classifying different subclasses of absence epilepsy.

1990 ◽  
Vol 138 ◽  
pp. 447-453
Author(s):  
G. Belvedere ◽  
M. R. E. Proctor

A simple mean-field model of a nonlinear stellar α-ω dynamo is considered, in which dynamo action is supposed to occur in a spherical shell, and where the main nonlinearity retained is the influence of the Lorentz force on the zonal flow field. The equations are simplified by truncating in the radial direction, while full latitudinal dependence is retained. The resulting nonlinear p.d.e.'s in latitude and time are solved numerically, and it is found that while regular dynamo wave type solutions are stable when the dynamo number D is sufficiently close to its critical value, there is a wide variety of stable solutions at larger values of D. Furthermore, two different types of dynamo can coexist at the same parameter values. Implications for fields in late-type stars are discussed.


2006 ◽  
Vol 355 (4-5) ◽  
pp. 352-357 ◽  
Author(s):  
Serafim Rodrigues ◽  
John R. Terry ◽  
Michael Breakspear

2009 ◽  
Vol 27 (3) ◽  
pp. 507-526 ◽  
Author(s):  
Serafim Rodrigues ◽  
David Barton ◽  
Robert Szalai ◽  
Oscar Benjamin ◽  
Mark P. Richardson ◽  
...  

2016 ◽  
Vol 79 (1) ◽  
pp. 11-20 ◽  
Author(s):  
A. Shukla ◽  
S. Åberg ◽  
A. Bajpeyi

2014 ◽  
Vol 2014 (1) ◽  
pp. 13D02-0 ◽  
Author(s):  
J. N. Hu ◽  
A. Li ◽  
H. Shen ◽  
H. Toki

2011 ◽  
Vol 20 (08) ◽  
pp. 1663-1675 ◽  
Author(s):  
A. BHAGWAT ◽  
Y. K. GAMBHIR

Systematic investigations of the pairing and two-neutron separation energies which play a crucial role in the evolution of shell structure in nuclei, are carried out within the framework of relativistic mean-field model. The shell closures are found to be robust, as expected, up to the lead region. New shell closures appear in low mass region. In the superheavy region, on the other hand, it is found that the shell closures are not as robust, and they depend on the particular combinations of neutron and proton numbers. Effect of deformation on the shell structure is found to be marginal.


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