Implicit and explicit adjustments to extrinsic visuo-motor transformations and their age-related changes

Area of Science:

• Neuroscience
• Human motor control
• Cognitive psychology

Background:

• Humans possess unique tool-use capabilities, requiring motor control adjustments for transformed movements.
• Visuo-motor transformations, such as hand movements to cursor motion, involve both implicit and explicit adjustments.
• Understanding these adjustments is key to comprehending human adaptability and aging effects on motor skills.

Purpose of the Study:

• To investigate the additive nature and functional independence of implicit and explicit visuo-motor adjustments.
• To examine how aging affects implicit and explicit adjustments to novel visuo-motor transformations.

Main Methods:

• Review of experimental studies on visuo-motor gain adjustments.
• Analysis of implicit (unconscious) and explicit (intentional) adaptation processes.
• Comparison of adjustment capabilities in different age groups.

Main Results:

• Implicit and explicit adjustments to novel visuo-motor gain were found to be additive.
• This additivity suggests functionally independent underlying processes for each adjustment type.
• Older adults showed impaired explicit adjustments, while implicit adjustments remained unaffected.

Conclusions:

• Implicit and explicit visuo-motor adaptation mechanisms operate independently.
• Aging selectively impairs explicit adaptation processes, highlighting a specific decline in intentional motor control.
• Implicit adaptation remains robust across the adult lifespan, suggesting preserved unconscious motor learning.