The effect of finger-movement speed of the dominant and the subdominant hand on cerebellar activation: A functional magnetic resonance imaging study

We studied the effects of different speeds of unimanual and bimanual moveme nts on functional magnetic resonance signal changes in the cerebellum. Six healthy consistently right-handed subjects were scanned at rest and while e xecuting a sequential finger-to-thumb-opposition task either unimanually (l eft or right hand) or bimanually. Movement frequency was paced by an audito ry signal at rates of either 1 or 3 Hz. Significant frequency-dependent blo od oxygen level-dependent signal increases were demonstrated ipsilaterally and contralaterally in the intermediate and lateral portions of the anterio r cerebellum for bimanual movements and for unimanual movements with the su bdominant hand. There was only a weak frequency-dependent effect for uniman ual movements performed with the dominant hand. In addition, signals were s tronger on the right intermediate zone of the anterior cerebellum for movem ents involving the right (dominant) hand while there was stronger activity on the left cerebellar hemisphere for movements involving the left (subdomi nant) hand. Taken together, these results suggest that rate and movement ta sk effects on cerebellar activation are differentially sensitive to subdomi nant and dominant hand movements. (C) 1999 Academic Press.