OBJECTIVE: To study rapidly alternating movements under fMRI in order to identify the brain regions that mediate increased complexity in bimanual vs unimanual movements and to verify the localization of a clinical test of limb ataxia (diadochokinesis). METHODS: Unimanual and bimanual movements, that is, palm(s) pronated then supinated, served as stimulation in a block design fMRI investigation at 1.5 T. Analyses compared bimanual movements and rest for each hand separately and the unimanual conditions combined. A pronation/supination task was chosen as it provides the same objective motor output during unimanual and bimanual formats. The increased coordination demand of the bimanual format (phase/antiphase movements) was expected to result in distinct activation in supplementary motor, primary motor, prefrontal, and cerebellar regions. RESULTS: The bimanual task uniquely elicited responses in specific anterior medial and posterior (vermal) cerebellar regions. CONCLUSIONS: The study corroborated clinical use of diadochokinesis tasks to test for aspects of cerebellar integrity. The data do not support the literature emphasizing basal ganglia mediation of this type of coordinated movement. Cerebellar medial and vermal regions (in connection with central nuclei) are proposed as the locus within the cerebellum for mediating complexity, that is, the effective integration of separate limb movements that proceed in an asynchronous but systematic fashion.
OBJECTIVE: To study rapidly alternating movements under fMRI in order to identify the brain regions that mediate increased complexity in bimanual vs unimanual movements and to verify the localization of a clinical test of limb ataxia (diadochokinesis). METHODS: Unimanual and bimanual movements, that is, palm(s) pronated then supinated, served as stimulation in a block design fMRI investigation at 1.5 T. Analyses compared bimanual movements and rest for each hand separately and the unimanual conditions combined. A pronation/supination task was chosen as it provides the same objective motor output during unimanual and bimanual formats. The increased coordination demand of the bimanual format (phase/antiphase movements) was expected to result in distinct activation in supplementary motor, primary motor, prefrontal, and cerebellar regions. RESULTS: The bimanual task uniquely elicited responses in specific anterior medial and posterior (vermal) cerebellar regions. CONCLUSIONS: The study corroborated clinical use of diadochokinesis tasks to test for aspects of cerebellar integrity. The data do not support the literature emphasizing basal ganglia mediation of this type of coordinated movement. Cerebellar medial and vermal regions (in connection with central nuclei) are proposed as the locus within the cerebellum for mediating complexity, that is, the effective integration of separate limb movements that proceed in an asynchronous but systematic fashion.
Authors: Mario Manto; James M Bower; Adriana Bastos Conforto; José M Delgado-García; Suzete Nascimento Farias da Guarda; Marcus Gerwig; Christophe Habas; Nobuhiro Hagura; Richard B Ivry; Peter Mariën; Marco Molinari; Eiichi Naito; Dennis A Nowak; Nordeyn Oulad Ben Taib; Denis Pelisson; Claudia D Tesche; Caroline Tilikete; Dagmar Timmann Journal: Cerebellum Date: 2012-06 Impact factor: 3.847
Authors: Bernhard Haslinger; Peter Erhard; Eckart Altenmüller; Andreas Hennenlotter; Markus Schwaiger; Helga Gräfin von Einsiedel; Ernst Rummeny; Bastian Conrad; Andrés O Ceballos-Baumann Journal: Hum Brain Mapp Date: 2004-07 Impact factor: 5.038