METHODOLOGICAL DEVELOPMENT

Localization of cortical rhythmic activity

 J. Kujala, M. Liljeström, R. Salmelin

Collaborators:

Cortical rhythmic activity is increasingly employed for characterizing human brain function. Using MEG, it is possible to localize the generators of these rhythms. Traditionally, the source locations have been estimated using sequential dipole modeling. Recently, two new methods for localizing rhythmic activity have been developed in our laboratiry, Dynamic Imaging of Coherent Sources (DICS) and Frequency-Domain Minimum Current Estimation (MCEFD). With new analysis methods emerging, the researcher faces the problem of choosing an appropriate strategy. We compared the performance and reliability of these three methods using both simulated and real data. All three approaches localized the principal sources of oscillatory activity very well. Dipole modeling is a very powerful tool once appropriate subsets of sensors have been selected. MCEFD provides simultaneous localization of sources and was found to give a good overview of the data. With DICS, it was possible to separate closeby sources that were not retrieved by the other two methods.

 Publications

  1. Liljeström M, Kujala J, Jensen O and Salmelin R:  Neuromagnetic localization of rhythmic activity in the human brain: a comparison of three methods. Neuroimage 2005, 25: 734-745.