Effects of aging on conditional visuomotor learning for grasping and lifting eccentrically weighted objects

Area of Science:

• Neuroscience
• Human Motor Control
• Aging Research

Background:

• Dexterous manipulation requires precise anticipatory force scaling.
• Previous work showed young adults can use explicit cues for motor learning.
• The impact of aging on using explicit cues for manipulation is unknown.

Purpose of the Study:

• To investigate if older adults can use explicit color cues about object center of mass (CM) location.
• To determine if aging affects the modulation of digit placement for dexterous manipulation based on explicit CM cues.
• To compare explicit cue learning with implicit learning in older adults.

Main Methods:

• Healthy older and young adults performed a manipulation task.
• Participants used arbitrary color cues indicating object CM location.
• Task involved exerting specific torque and minimizing object tilt during lifting.

Main Results:

• Older adults exhibited greater torque error and slower learning than young adults.
• Older adults showed impaired anticipatory modulation of digit position with explicit CM cues.
• This impairment was not observed when CM location was implicitly conveyed.

Conclusions:

• Aging impairs the ability to use explicit cues for conditional learning in dexterous manipulation.
• Older adults show specific deficits in learning to modulate digit position based on explicit object properties.
• Implicit learning mechanisms for manipulation appear preserved in older adults.