Concurrent adaptation to opposing visual displacements during an alternating movement

Area of Science:

• Motor control
• Human adaptation
• Neuroplasticity

Background:

• Previous research suggested similar adaptation rates for alternating bimanual and unimanual movements under visual rotation.
• However, prior studies used blocks of trials, not strict limb alternation.

Purpose of the Study:

• To investigate adaptation rates during strictly alternating unimanual and bimanual movements with opposing visual rotations.
• To determine if separate limbs serve as contextual cues for adaptive states.
• To identify factors contributing to interference during alternating movements.

Main Methods:

• Subjects performed alternating left/right hand movements with opposing cursor rotations.
• Adaptation rates were compared between unimanual and alternating bimanual conditions.
• Control conditions were used to rule out visual switching or limb alternation as primary causes of interference.

Main Results:

• Both left and right hands adapted to opposing rotations at similar rates during alternating conditions, forming concurrent adaptive states.
• Online correction during alternating movements was significantly slower than in unimanual conditions.
• Negative interference in alternating conditions was not due to limb alternation or visual eye switching.

Conclusions:

• Separate limbs can act as contextual cues to switch between adaptive states.
• A significant interference effect occurs during online correction in alternating bimanual tasks.
• This interference may stem from the need to dissociate visual information from alternating limb movements for online control.