title: Separating slow BOLD from non-BOLD baseline drifts using multi-echo fMRI.
abstract: The functional magnetic resonance (fMRI) baseline is known to drift over the course of an experiment and is often attributed to hardware instability. These ultraslow fMRI fluctuations are inseparable from blood oxygenation level dependent (BOLD) changes in standard single echo fMRI and they are therefore typically removed before further analysis in both resting-state and task paradigms. However, some part of these fluctuations may be of neuronal origin, as neural activity can indeed fluctuate at the scale of several minutes or even longer, such as after the administration of drugs or during the ultradian rhythms. Here, we show that it is possible to separate the slow BOLD and non-BOLD drifts automatically using multi-echo fMRI and multi-echo independent components analysis (ME-ICA) denoising by demonstrating the detection of a visual signal evoked from a flickering checkerboard with slowly changing contrast.
authors.affiliation: Section on Functional Imaging Methods, LBC, NIMH, NIH, Bethesda, MD, USA. Electronic address: jennifer.evans@nih.gov.
authors.forename: Jennifer W
authors.initials: JW
authors.lastname: Evans
authors.affiliation: Section on Functional Imaging Methods, LBC, NIMH, NIH, Bethesda, MD, USA.
authors.forename: Prantik
authors.initials: P
authors.lastname: Kundu
authors.affiliation: Human Motor Control Section, MNB, NINDS, NIH, Bethesda, MD, USA.
authors.forename: Silvina G
authors.initials: SG
authors.lastname: Horovitz
authors.affiliation: Section on Functional Imaging Methods, LBC, NIMH, NIH, Bethesda, MD, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Bandettini
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D055815:Young Adult
keywords: BOLD; Denoising; Multi-echo; Non-BOLD; Slow drift; fMRI