Activation of Pre–Supplementary Motor Area (SMA) and SMA Proper During Unimanual and Bimanual Complex Sequences: An Analysis Using Functional Magnetic Resonance Imaging

Abstract

Several functional imaging studies have shown that the extent of activation and percentage change in cerebral blood flow in the supplementary motor area (SMA) during a bimanual mirror performance of a simple repetitive movement are almost identical to those during a unimanual movement. The aim of this study was to investigate whether this finding was also applicable to a more complex movement. Eight right-handed, healthy volunteers performed unimanually (with their right and left hands) and bimanually (in a mirror fashion) thumb-finger opposition in a nonconsecutive order (index-middle-index-ring-index-little-index-middle ... fingers). The SMA proper was more activated during the bimanual movement than the unimanual movement with either hand. This is in accordance with the hypothesis that bimanual movement, even in a mirror fashion, is more difficult than unimanual movement when the task is complex but not when the task is simple. Pre-SMA was inconsistently activated. The results suggest that the SMA proper plays an active role in executive processing during bimanual mirror performance of complex movements.

Perturbations in Action Goal Influence Bimanual Grasp Posture Planning

“…Second, when a perturbation in action goal occurred, participants were more likely to modify their grasp postures during C. M. L. Hughes & C. Seegelke unimanual object manipulations, compared to when two objects were manipulated (i.e., bimanual object manipulation). The decrease in end-state comfort compliance in nonperturbed trials, as well as the reduced ability to modify grasp posture plans to comply with end-state comfort in perturbed trials during bimanual (relative to unimanual) object manipulation, are consistent with previous behavioral (Hughes & Franz, 2007, 2008Kunde & Weigelt, 2005) and neuroimaging studies (Debaere et al, 2001;Sadato, Yonekura, Waki, Yamada, & Ishii, 1997;Toyokura, Muro, Komiya, & Obara, 2002) demonstrating that planning and executing simultaneous bimanual movements require greater cognitive resources than unimanual actions.…”

Attention Allocation and Task Representation during Joint Action Planning

“…This hypothesis is consistent with previous intracranial and source localization studies, which have associated the late stages of the MRP with SMA activation (Ikeda et al, 1995;Toro, Matsumoto, Deuschl, Roth, & Hallett, 1993). The SMA has a crucial role in the temporal coordination of movements (Cunnington, Bradshaw, & Iansek, 1996), and it is more strongly activated during bimanual compared with unimanual movements (Toyokura, Muro, Komiya, & Obara, 2002;Ikeda et al, 1995). With regards to our experiment, this implies that the enlarged MRP during joint action planning reflects the demand for coordination of two impending actions (much like in bimanual movements) to successfully perform the joint task.…”

Sleep-dependent learning and motor-skill complexity

“…The latter hypothesis is supported by several lines of physiological evidence, in animals and humans, indicating that bimanual complex movements engage somewhat different neural systems in cortical (Gordon et al 1998;Kazennikov et al 1999;Jancke et al 2000;Toyokura et al 2002;Nair et al 2003) and subcortical (Wannier et al 2002) regions, as well as in the cerebellum (Tracy et al 2001). Furthermore, on the basis of the known somatotopy of the motor cortex and cerebellum (Rijntjes et al 1999;Kurth et al 2000;Beisteiner et al 2001), the size of networks involved in controlling movements appears to vary as a function of the number of digits used in task performance.…”