Whole-brain functional MR imaging activation from a finger-tapping task examined with independent component analysis

BACKGROUND AND PURPOSE: Independent component analysis (ICA), unlike other methods for processing functional MR (fMR) imaging data, requires no a prio ri assumptions about the hemodynamic response to the task. The purpose of t his study was to analyze the temporal characteristics and the spatial mappi ng of the independent components identified by ICA when the subject perform s a finger-tapping task. METHODS: Ten healthy subjects performed variations of the finger-tapping ta sk conventionally used to map the sensorimotor cortex. The scan data, were processed with ICA, and the temporal configuration of the components and th eir spatial localizations mere studied. The locations with activation were tabulated and compared with locations known to be involved in the organizat ion of motor functions in the brain. RESULTS: Components were identified that correlated to varying degrees with the conventional boxcar reference function. One or more of these component s mapped to the sensorimotor cortex, supplementary motor area (SMA), putame n, and thalamus, By means of ICA components, sensorimotor cortex, supplemen tary motor area, and superior cerebellar activation were identified bilater ally in 100% of the subjects; thalamus activation was contralateral to the active hand in 80%; and putamen activation was contralateral to the active hand in 60%, CONCLUSION: ICA processing of multislice fMR imaging data acquired during f inger tapping identifies the sensorimotor cortex, SMA, cerebellar, putamen, and thalamic activation. ICA appears to be a method that provides informat ion on both the temporal and spatial characteristics of activation. Multipl e task-related components can be identified by ICA, and specific activation maps can be derived from each separate component.