Global optimization in the localization of neuromagnetic sources.
The locations of active brain areas can be estimated from the magnetic field produced by the neural current sources. In many cases, the actual current distribution can be modeled with a set of stationary current dipoles with time-varying amplitudes. This work studies global optimization methods that find the minimum of the least-squares error function of the current dipole estimation problem. Three different global optimization methods were investigated: clustering method, simulated annealing, and genetic algorithms. In simulation studies, the genetic algorithm was the most effective method. The methods were also applied to analysis of actual measurement data.
Uutela
K
K
Low Temperature Laboratory, Helsinki University of Technology, Finland. Kimmo.Uutela@hut.fi
Hämäläinen
M
M
Salmelin
R
R
D000465:Algorithms; D005072:Evoked Potentials, Auditory; D006801:Humans; D007807:Language Tests; D016018:Least-Squares Analysis; D016014:Linear Models; D015225:Magnetoencephalography; D008959:Models, Neurological; D012016:Reference Values; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D014793:Visual Cortex / Q000502:physiology*