(Non)stationarity of temporal dynamics in fMRI

V. Calhoun, T. Adali, G. Pearlson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Estimation of the temporal information encoded in the observed hemodynamic response in functional MRI (fMRI) is of great interest. One assumption that most of the current studies make is that the mean waveform observed is consistently locked with the stimulus and variably distributed about its mean. Because the noise is high any violations of this assumption are not easily observed. We have developed a method for filtering and tracking the hemodynamic response using a recursive least squares (RLS) algorithm and probabilistic shift maps (psm). Our initial results clearly demonstrate an overall change in the amplitude from greater to lesser and a latency shift from shorter to longer in primary visual cortex. These changes may indicate fatigue or adaptation of the neuronal patterns or blood supply. The fact that we observe a change in primary visual cortex is notable since this suggests that changes in brain regions which are specialized for higher congnitive functions may exhibit even larger changes. This suggests the importance of determining the degree to which the measured brain region adapts to the paradigm presented in any fMRI experiment.

Original languageEnglish (US)
Title of host publicationAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
PublisherIEEE
Number of pages1
ISBN (Print)0780356756
StatePublished - Dec 1 1999
EventProceedings of the 1999 IEEE Engineering in Medicine and Biology 21st Annual Conference and the 1999 Fall Meeting of the Biomedical Engineering Society (1st Joint BMES / EMBS) - Atlanta, GA, USA
Duration: Oct 13 1999Oct 16 1999

Publication series

NameAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
Volume2
ISSN (Print)0589-1019

Other

OtherProceedings of the 1999 IEEE Engineering in Medicine and Biology 21st Annual Conference and the 1999 Fall Meeting of the Biomedical Engineering Society (1st Joint BMES / EMBS)
CityAtlanta, GA, USA
Period10/13/9910/16/99

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ASJC Scopus subject areas

  • Signal Processing
  • Biomedical Engineering
  • Computer Vision and Pattern Recognition
  • Health Informatics

Cite this

Calhoun, V., Adali, T., & Pearlson, G. (1999). (Non)stationarity of temporal dynamics in fMRI. In Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings (Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings; Vol. 2). IEEE.