ACTIVATION OF THE CEREBELLUM BY SENSORY FINGER STIMULATION AND BY FINGER OPPOSITION MOVEMENTS - A FUNCTIONAL MAGNETIC-RESONANCE-IMAGING STUDY

Activation of the ipsilateral anterior robe of the cerebellum by means of hand movements by humans is a well-known phenomenon, but the cereb ellar encoding of sensory information has not been well established. T he authors delineated the representation of sensory stimulation of fin gers in the anterior lobe of the cerebellum using functional magnetic resonance imaging sensitized to changes in blood oxygenation and compa red these areas to the regions activated by means of finger opposition movements. Activation was determined by means of pixel-by-bixel corre lation of the signal intensity time course with a reference waveform e quivalent to the stimulus protocol. All subjects showed significant ac tivation of the anterior lobe of the cerebellum, mainly located in the ipsilateral Larsell lobules IV-V and less consistent in the vermis in relation to sensory finger stimulation. Among some subjects the autho rs also found activation in the anterior lobe on the contralateral sid e. The finger movements activated regions that overlapped with the are as activated by sensory finger stimulation but showing a larger and mo re intense activation pattern.