Interhemispheric motor cortex influence during bimanual unloading.

Using the transcranial magnetic stimulation (TMS) of motor cortex we examined changes in the motor evoked potential (MEP) during natural bimanual unloading, during lifting of an equivalent weight by the contralateral arm while the ipsilateral forearm was held stationary (CONTRA) and during practice of unnatural unloading. During natural unloading, MEP amplitude decreased proportionally to the muscle activity. In CONTRA task MEP amplitude decreased, but the muscle activity was not changed.

Bimanual coordination of bowing and fingering in violinists--effects of position changes and string changes.

Music performance is based on demanding motor control with much practice from young age onward. We have chosen to investigate basic bimanual movements played by violin amateurs and professionals. We posed the question whether position and string changes, two frequent mechanisms, may influence the time interval bowing (right)-fingering (left) coordination.

Anticipatory postural adjustment: the role of motor cortex in the natural and learned bimanual unloading.

Anticipatory postural adjustment (APA) during bimanual action is observed when participants hold an object in one hand and then lift that object with the other hand. The decrease in activity of a forearm flexor muscle prior to an active forearm unloading acts to stabilize the forearm position. Recent studies have investigated the influence of the corticospinal system on muscle activity during APA through transcranial magnetic stimulation.

Goal synchronization of bimanual skills depends on proprioception.

The present experiments in Human subjects were designed to test whether proprioceptive feedback plays a role in optimising bimanual synchronization in a goal-oriented familiar task. Goal-synchronization is a typical feature of bimanual everyday skills. The purpose of the study was to disturb proprioceptive signalling by means of vibrating the leading left limb while subjects performed a bimanual task on a drawer manipulandum.

TMS-responses during anticipatory postural adjustment in bimanual unloading in humans.

Transcranial magnetic brain stimulation (TMS) was used to assess the influence of the corticospinal system on motor output during forearm unloading in humans. Unloading was obtained either "passively" by the experimenter, or "actively" with the subjects' own contralateral arm. Anticipatory postural adjustments consisted of changes in the activity of a forearm flexor muscle prior to active unloading of the limb and acted to stabilize the forearm position.

Coordination of bowing and fingering in violin playing.

Playing string instruments implies motor skills including asymmetrical interlimb coordination. How special is musical skill as compared to other bimanually coordinated, non-musical skillful performances? We succeeded for the first time to measure quantitatively bimanual coordination in violinists playing repeatedly a simple tone sequence. A motion analysis system was used to record finger and bow trajectories for assessing the temporal structure of finger-press, finger-lift (left hand), and bow stroke reversals (right arm).