Developmental changes in unimanual and bimanual aiming movements

Area of Science:

• Developmental neuroscience
• Motor control
• Human movement science

Background:

• Reaction time (RT) and movement time (MT) are key indicators of motor development.
• Understanding how bimanual and unimanual movements evolve with age is crucial for assessing neurological maturation.

Purpose of the Study:

• To analyze the developmental changes in reaction time (RT) and movement time (MT) for unimanual and bimanual movements across different age groups.
• To investigate the influence of age and sex on these changes in motor performance.

Main Methods:

• Participants aged 5, 8, and 11 years performed unimanual, bimanual symmetrical, and bimanual nonsymmetrical aiming movements.
• Reaction time (RT) and movement time (MT) were recorded and analyzed across the three movement conditions and age groups.

Main Results:

• Younger children (5 years) showed shorter RTs for bimanual symmetrical movements compared to unimanual and nonsymmetrical.
• By age 8, bimanual nonsymmetrical movements still had longer RTs, but unimanual and symmetrical movements became similar.
• Movement time (MT) showed an advantage for unimanual over bimanual symmetrical movements in younger children, while nonsymmetrical movements were consistently slower.

Conclusions:

• The development of RT and MT reflects the maturation of interhemispheric information transfer, linked to corpus callosum function.
• Improved interhemispheric transfer facilitates contralateral motor inhibition and complex bilateral coordination.
• Slower maturation of movement feedback compared to feed-forward information may explain the prolonged evolution of movement time.