In my master thesis I studied the dynamics of the sinus node by means of modelling and simulation, in cooperation with the physiologist Björn Wohlfart and my physics tutor Gunnar Ohlén. The sinus node is the natural pacemaker of the heart and is placed in the right atrium. It consists of hundreds of thousands individual pacemaker cells, each of which acts as an electric oscillator with its own natural frequency. All of these cells have to be sufficiently coupled in order to synchronize to a common frequency and initiate a regular heartbeat. I carried this subject with me as a started my PhD-studies. After a while, my research became more abstract, focusing on general properties of synchronization in large assemblies of limit cycle oscillators with varying natural frequencies. Such synchronization can be compared to a phase transition, in which the level of order in a medium suddenly increases as a parameter changes. The most well-known examples are water that freezes and metal that becomes magnetic as the temperature drops.
Complex wave fronts in a synchronized oscillator lattice
Simulations of sinus nodal behaviour
Master thesis, April 24, 1998.
Dynamics of the sinus node during poor intercellular coupling
Licentiate thesis, May 2, 2001.
Östborn P., Wohlfart B., Ohlen G.
Journal of Theoretical Biology 211(3), pp 201-217, 2001
Östborn P., Ohlen G., Wohlfart W.
Journal of Theoretical Biology 211(3), pp 219-227, 2001
Functional role of the connective tissue and the gap junction distribution in the sinus node
To be submitted to Journal of Theoretical Biology
Physical Review E 66, 016105, July 2002
Östborn P., Åberg S., Ohlen G.
Physical Review E 68, 015104(R), July 2003
Phase transitions in large oscillator lattices
PhD thesis, November 21, 2003.
Physical Review E 70, 016120, July 2004
Sträng J. E., Östborn P.
Physical Review E 72, 056137, November 2005
Physical Review E 79, 051114, May 2009