Instabilities during antiphase bimanual movements: are ipsilateral pathways involved?

Area of Science:

• Neuroscience
• Motor Control
• Human Movement Science

Background:

• Bimanual coordination is generally stable with homologous muscles (in-phase movements).
• Asymmetric movements using nonhomologous muscles are less stable and tend to shift to in-phase coordination.
• Ipsilateral corticospinal pathways are hypothesized to mediate instability in antiphase movements.

Purpose of the Study:

• To investigate the role of ipsilateral corticospinal pathways in bimanual coordination.
• To determine if the presence of ipsilateral motor-evoked potentials (MEPs) correlates with bimanual movement variability.

Main Methods:

• Participants performed a bimanual circling task.
• Transcranial magnetic stimulation (TMS) was used to elicit motor-evoked potentials (MEPs).
• MEPs were assessed for distal ipsilateral pathways to categorize participants.

Main Results:

• Participants with elicitable ipsilateral MEPs showed greater variability in the bimanual circling task.
• This suggests a link between ipsilateral pathway activation and reduced bimanual coupling stability.
• The findings support the role of ipsilateral control in phenomena like movement uncoupling.

Conclusions:

• Ipsilateral neural pathways significantly influence bimanual coordination.
• The presence of ipsilateral control may contribute to the instability observed in asymmetric bimanual movements.
• Targeting ipsilateral pathways could offer insights into improving motor control and coordination.