Cervical spinal cord stimulation disrupts proprioception yet improves voluntary arm reaching

Area of Science:

• Neuroscience
• Motor Control
• Rehabilitation Science

Background:

• The necessity of proprioception for upper-limb motor control remains debated.
• Previous studies on deafferented subjects are confounded by long-term adaptation.
• A causal test is needed to determine proprioception's role in movement.

Purpose of the Study:

• To causally investigate the role of proprioception in upper-limb motor control.
• To determine if disrupting proprioception affects rapid, goal-directed arm reaching.
• To leverage cervical spinal cord stimulation (SCS) in post-stroke individuals.

Main Methods:

• Utilized a clinical trial involving cervical spinal cord stimulation (SCS).
• Assessed the causal effects of SCS-induced proprioceptive perturbation on motor control.
• Measured changes in arm reaching kinematics and proprioceptive perception.

Main Results:

• Cervical spinal cord stimulation (SCS) ON causally impaired proprioceptive perception and postural stability.
• SCS enhanced adaptation to visual errors during implicit learning.
• Rapid, goal-directed reaching (both visual and non-visual) improved in smoothness, straightness, and accuracy.

Conclusions:

• Proprioception is not required for rapid, goal-directed upper-limb movements.
• These findings provide strong causal evidence resolving the debate on proprioception's necessity.
• This research offers insights into motor control mechanisms and stroke rehabilitation.