Automatic Parameter-Range Estimation for Cardiac Cells Radu Grosu SUNY at Stony Brook Joint work with Ezio Bartocci, Gregory Batt, Flavio H. Fenton, James Glimm, Colas Le Guernic, and Scott A. Smolka
Excitable Cells • Generate action potentials (elec. pulses) in response to electrical stimulation – Examples: neurons, cardiac cells, etc. • Local regeneration allows electric signal propagation without damping • Building block for electrical signaling in brain, heart, and muscles
Excitable Cells – Examples: neurons, cardiac cells, etc. Neurons of a squirrel University College London Artificial cardiac tissue University of Washington
Excitable Cells Neurons of a squirrel • Local regeneration allows electric signal University College London propagation without damping Artificial cardiac tissue University of Washington
Excitable Cells Neurons of a squirrel University College London • Building block for electrical signaling in brain, heart, and muscles Artificial cardiac tissue University of Washington
Single Cell Reaction: Action Potential Membrane’s AP depends on: Schematic Action Potential • Stimulus (voltage or current): – External / Neighboring cells • Cell’s state (excitable or not): voltage – Parameters value Threshold Resting potential time
Single Cell Reaction: Action Potential Schematic Action Potential • Cell’s state (excitable or not): voltage – Parameters value Threshold Resting potential time
Single Cell Reaction: Action Potential Schematic Action Potential voltage Threshold failed initiation Resting potential time
Single Cell Reaction: Action Potential Schematic Action Potential nonlinear voltage Threshold failed initiation Resting potential time
Single Cell Reaction: Action Potential Schematic Action Potential nonlinear voltage Threshold Tissue: Reaction / diffusion u failed initiation t R ( u ) ( D u ) Resting potential time
Single Cell Reaction: Action Potential Schematic Action Potential nonlinear voltage Threshold Tissue: Reaction / diffusion u failed initiation t R ( u ) ( D u ) Resting potential time Behavior In time
Single Cell Reaction: Action Potential Schematic Action Potential nonlinear voltage Threshold Tissue: Reaction / diffusion u failed initiation t R ( u ) ( D u ) Resting potential time Reaction
Single Cell Reaction: Action Potential Schematic Action Potential nonlinear voltage Threshold Tissue: Reaction / diffusion u failed initiation t R ( u ) ( D u ) Resting potential time Diffusion
Lack of Excitability: Implications Stimulus: bottom row, every 300ms Obstacle of UT No Obstacle
Problem to Solve • What circumstances lead to a loss of excitability? • What parameter ranges reproduce loss of excitability?
Problem to Solve • What parameter ranges reproduce loss of excitability?
Problem to Solve • What parameter ranges reproduce loss of excitability? Experimental Minimal Minimal Data Resistor Model Conductor Model RoverGene Minimal Analysis Tool Multi-Affine Model
Biological Switching u 1 0 u 1 R ( u , 1 , 2 ,0,1) else 2 1 1 S ( u , , k ,0,1) u 2 1 1 e 2 k ( u ) 0.5 k 16 0 u H ( u , ,0,1) 1 u
Minimal Resistor Model: Voltage ODE u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u ))
Minimal Resistor Model: Voltage ODE u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) Voltage Rate
Minimal Resistor Model: Voltage ODE u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) Diffusion Laplacian
Minimal Resistor Model: Voltage ODE u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) Fast input current
Minimal Resistor Model: Voltage ODE u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) Slow input current
Minimal Resistor Model: Voltage ODE u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) Slow output current
MRM: Currents Equations u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) J si ( u , w , s ) H ( u , w ,0,1) ws / si H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u )
MRM: Currents Equations Heaviside u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) (step) H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) J si ( u , w , s ) H ( u , w ,0,1) ws / si H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u )
MRM: Currents Equations Constant u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) Resistanc e H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) J si ( u , w , s ) H ( u , w ,0,1) ws / si H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u )
MRM: Currents Equations u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) Piecewise Nonlinear J si ( u , w , s ) H ( u , w ,0,1) ws / si H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u )
MRM: Currents Equations u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) J si ( u , w , s ) H ( u , w ,0,1) ws / si Piecewise H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u ) Bilinear
MRM: Currents Equations u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) J si ( u , w , s ) H ( u , w ,0,1) ws / si H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u ) Piecewise Sigmoidal Resistanc Resistanc e e
MRM: Currents Equations u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) J si ( u , w , s ) H ( u , w ,0,1) ws / si H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u ) Piecewise Nonlinear
MRM: Gates ODEs u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) J si ( u , w , s ) H ( u , w ,0,1) ws / si H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u ) H ( u , v ,0,1) ( v v ) / v ( u ) H ( u , v ,0,1) v / v v ( u , v ) w ( u , w ) H ( u , w ,0,1)( w w ) / w ( u ) H ( u , w ,0,1) w / w & ( S ( u , u s , k s ,0,1) s ) / s ( u ) s ( u , s ) & H ( u v )( u v )( u u u ) v / fi J fi
MRM: Gates ODEs u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) J si ( u , w , s ) H ( u , w ,0,1) ws / si Piecewise H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u ) Resistance H ( u , v ,0,1) ( v v ) / v ( u ) H ( u , v ,0,1) v / v v ( u , v ) w ( u , w ) H ( u , w ,0,1)( w w ) / w ( u ) H ( u , w ,0,1) w / w & ( S ( u , u s , k s ,0,1) s ) / s ( u ) s ( u , s ) & H ( u v )( u v )( u u u ) v / fi J fi Piecewise Resistance
MRM: Gates ODEs u ( u , v , w , s ) ( D u ) ( J fi ( u , v ) J si ( u , w , s ) J so ( u )) H ( u , v ,0,1) ( u v )( u u u ) v / fi J fi ( u , v ) J si ( u , w , s ) H ( u , w ,0,1) ws / si H ( u , w ,0,1) u / o ( u ) H ( u , w ,0,1) / so ( u ) J so ( u ) H ( u , v ,0,1) ( v v ) / v ( u ) H ( u , v ,0,1) v / v v ( u , v ) w ( u , w ) H ( u , w ,0,1)( w w ) / w ( u ) H ( u , w ,0,1) w / w & ( S ( u , u s , k s ,0,1) s ) / s ( u ) s ( u , s ) & Sigmoidal Resistance H ( u v )( u v )( u u u ) v / fi J fi Sigmoid
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