BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Uncertainty Quantification in the Parameterization of Cardiac Acti
 on Potential Models Through the Singular Value Decomposition - Samuel Wall
  (Simula Research Laboratory)
DTSTART:20190606T143000Z
DTEND:20190606T150000Z
UID:TALK125665@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:Mathematical   models describing cardiac action potential dyna
 mics are highly used to   understand processes that may disrupt the normal
  electrical activity of the   heart.&nbsp\; However\, these models\,   con
 sisting of biophysical descriptions of ion flux and transport across   mem
 branes and through the cell\, are heavily\, heterogeneously\, and   non-un
 iquely parameterized\, leading to significant uncertainty in their   predi
 ctions.&nbsp\; Here we investigate this   uncertainty\, in the context of 
 model parameterization through adjustment of   the maximum conductances of
  the individual contributing ionic cellular   currents.&nbsp\; It has been
  well described   that non-unique solutions exist for given action potenti
 al dynamics using   this approach\, and we present a method for quantifyin
 g the uncertainty in   this framework.&nbsp\; Our key question is   this: 
 How can the maximum conductances of a model be changed without giving   ap
 preciable changes to a given action potential? We probe this question usin
 g   a method founded on the singular value decomposition of a matrix built
  from   the contribution from all the individual ion currents over the tim
 e course of   an action potential. When small singular values of this matr
 ix are present\,   there exist identifiable combinations of currents that 
 will lead to no or   minimal change to the overall voltage waveform.&nbsp\
 ; We test this method across a range of   cardiac models\, quantifying par
 ameter uniqueness in each case\, and testing   whether the conclusion from
  linear analysis of the matrix of currents carries   over to provide insig
 ht in the uniqueness of the parameters in the non-linear   case.
LOCATION:Seminar Room 1\, Newton Institute
END:VEVENT
END:VCALENDAR