Explicit knowledge about the availability of visual feedback affects grasping with the left but not the right hand

Area of Science:

• Neuroscience
• Motor Control
• Human Movement Science

Background:

• Previous studies show trial history influences right-hand grasping, not anticipatory knowledge of visual feedback.
• The behavior of the non-dominant left hand under similar feedback conditions remains unexplored.

Purpose of the Study:

• To compare peak grip aperture (PGA) for left- and right-hand grasps under varying visual feedback conditions and trial schedules.
• To investigate the influence of trial history versus anticipatory knowledge on grasping with each hand.

Main Methods:

• Right-handed individuals performed grasps with visual feedback (closed-loop) and without (open-loop).
• Trials were presented in blocked, randomized, or alternating schedules.
• Peak grip aperture (PGA) was measured for both left and right hands.

Main Results:

• Right-hand grasps showed homogenization of PGA across conditions when trials were mixed, driven solely by trial history.
• Left-hand grasps were influenced by both trial history and anticipatory knowledge of feedback, but only on closed-loop trials.
• Left-hand open-loop grasps showed consistent large PGAs regardless of feedback schedule, with no homogenization observed.

Conclusions:

• Right-hand grasping pre-movement programming relies on previous trial events.
• Left-hand grasping programming is more cognitively controlled, utilizing explicit trial order information to anticipate upcoming feedback.
• The findings highlight distinct neural mechanisms underlying dominant and non-dominant hand motor control.