title: The activity in the contralateral primary motor cortex, dorsal premotor and supplementary motor area is modulated by performance gains.
abstract: There is growing experimental evidence that the engagement of different brain areas in a given motor task may change with practice, although the specific brain activity patterns underlying different stages of learning, as defined by kinematic or dynamic performance indices, are not well understood. Here we studied the change in activation in motor areas during practice on sequences of handwriting-like trajectories, connecting four target points on a digitizing table "as rapidly and as accurately as possible" while lying inside an fMRI scanner. Analysis of the subjects' pooled kinematic and imaging data, acquired at the beginning, middle, and end of the training period, revealed no correlation between the amount of activation in the contralateral M1, PM (dorsal and ventral), supplementary motor area (SMA), preSMA, and Posterior Parietal Cortex (PPC) and the amount of practice per-se. Single trial analysis has revealed that the correlation between the amount of activation in the contralateral M1 and trial mean velocity was partially modulated by performance gains related effects, such as increased hand motion smoothness. Furthermore, it was found that the amount of activation in the contralateral preSMA increased when subjects shifted from generating straight point-to-point trajectories to their spatiotemporal concatenation into a smooth, curved trajectory. Altogether, our results indicate that the amount of activation in the contralateral M1, PMd, and preSMA during the learning of movement sequences is correlated with performance gains and that high level motion features (e.g., motion smoothness) may modulate, or even mask correlations between activity changes and low-level motion attributes (e.g., trial mean velocity).
authors.affiliation: Department of Neurobiology, Brain Research, Weizmann Institute of Science Rehovot, Israel ; Department of Computer Science and Applied Mathematics, Weizmann Institute of Science Rehovot, Israel.
authors.forename: Ronen
authors.initials: R
authors.lastname: Sosnik
authors.affiliation: Department of Computer Science and Applied Mathematics, Weizmann Institute of Science Rehovot, Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Flash
authors.affiliation: Faculty of Medicine, Goldschleger Eye Research Institute, Tel Aviv University Tel Hashomer, Israel.
authors.forename: Anna
authors.initials: A
authors.lastname: Sterkin
authors.affiliation: Department of Neurology, Segeberger Kliniken Bad Segeberg, Germany ; Department of Therapeutic Sciences, MSH Medical School Hamburg Hamburg, Germany.
authors.forename: Bjoern
authors.initials: B
authors.lastname: Hauptmann
authors.affiliation: Faculty of Education, Department of Learning Disabilities, The Brain Behavior Research Center, University of Haifa Haifa, Israel.
authors.forename: Avi
authors.initials: A
authors.lastname: Karni
keywords: co-articulation; fMRI; motion smoothness; motor learning; movement sequence