Independent component analysis of nondeterministic fMRI signal sources.
Neuronal activation can be separated from other signal sources of functional magnetic resonance imaging (fMRI) data by using independent component analysis (ICA). Without deliberate neuronal activity of the brain cortex, the fMRI signal is a stochastic sum of various physiological and artifact related signal sources. The ability of spatial-domain ICA to separate spontaneous physiological signal sources was evaluated in 15 anesthetized children known to present prominent vasomotor fluctuations in the functional cortices. ICA separated multiple clustered signal sources in the primary sensory areas in all of the subjects. The spatial distribution and frequency spectra of the signal sources correspond to the known properties of 0.03-Hz very-low-frequency vasomotor waves in fMRI data. In addition, ICA was able to separate major artery and sagittal sinus related signal sources in each subject. The characteristics of the blood vessel related signal sources were different from the parenchyma sources. ICA analysis of fMRI can be used for both assessing the statistical independence of brain signals and segmenting nondeterministic signal sources for further analysis.
Kiviniemi
Vesa
V
Department of Diagnostic Radiology, University of Oulu, Oulu, Finland. vkivinie@mail.student.oulu.fi
Kantola
Juha-Heikki
JH
Jauhiainen
Jukka
J
Hyvärinen
Aapo
A
Tervonen
Osmo
O
D016477:Artifacts; D001303:Auditory Cortex / Q000098:blood supply / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008432:Mathematical Computing; D010101:Oxygen Consumption / Q000502:physiology; D025341:Principal Component Analysis; D012039:Regional Blood Flow / Q000502:physiology; D013003:Somatosensory Cortex / Q000098:blood supply / Q000502:physiology; D013269:Stochastic Processes; D014666:Vasomotor System / Q000502:physiology; D014793:Visual Cortex / Q000098:blood supply / Q000502:physiology