Dear SPM list,
Has anybody had experience trying to model explicitly (as a confounding
variable) the part of the signal in fMRI that may be coming from large
blood vessels? Since, to my understanding, signal from large blood vessels
does not reflect local neural activity (and is instead influenced by
the pooled neural activity over rather large and sometimes distant brain
regions), it seems that it would be reasonable to try to exclude this
variance from the activation maps.
Presumably, the signal coming from such large vessels (or at least
large veins) has a later onset and peak, and it should therefore be
possible, at least in principle, to model it explicitly and exclude the
variance due it. Has anybody tried that before and what would an
appropriate (late) onset be? Anyone's thoughts or experience would be
greatly appreciated.
Best regards,
-k.
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Kalina Christoff Email: [log in to unmask]
Office: Rm.478; (650) 725-0797
Department of Psychology Home: (650) 497-7170
Jordan Hall, Main Quad Fax: (650) 725-5699
Stanford, CA 94305-2130 http://www-psych.stanford.edu/~kalina/
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