@article{
    Ylipaavalniemi09,
    author = "Ylipaavalniemi, Jarkko and Savia, Eerika and Malinen, Sanna and Hari, Riitta and Vig{\'a}rio, Ricardo and Kaski, Samuel",
    responsibleauthor = "Kaski, Samuel",
    doi = "10.1016/j.neuroimage.2009.03.056",
    title = "Dependencies between stimuli and spatially independent {fMRI} sources: Towards brain correlates of natural stimuli",
    url = "http://dx.doi.org/10.1016/j.neuroimage.2009.03.056",
    journal = "Neuro{I}mage",
    corerank = "NA",
    abstract = "Natural stimuli are increasingly used in functional magnetic resonance imaging ({fMRI}) studies to imitate real-life situations. Consequently, challenges are created for novel analysis methods, including new machine learning tools. With natural stimuli it is no longer feasible to assume single features of the experimental design alone to account for the brain activity. Instead, relevant combinations of rich-enough stimulus features could explain the more complex activation patterns.\par We propose a novel two-step approach, where independent component analysis is first used to identify spatially independent brain processes, which we refer to as \emph{functional patterns}. As the second step, temporal dependencies between stimuli and functional patterns are detected using canonical correlation analysis. Our proposed method looks for combinations of stimulus features and the corresponding combinations of functional patterns.\par This two-step approach was used to analyze measurements from a {fMRI} study during multi-modal stimulation. The detected complex activation patterns were explained as resulting from interactions of multiple brain processes. Our approach seems promising for analysis of data from studies with natural stimuli.",
    volume = "48",
    flags = "AIRC HIIT public",
    year = "2009",
    internalpdf = "ylipaavalniemi09.pdf",
    impactfactor = "A",
    pages = "176--185"
}