Spontaneous and random baby movements help develop the sensorimotor system

Spontaneous, random movements in babies help develop their sensorimotor systems, according to new research led by the University of Tokyo. Combining the detailed motion her capture of newborns and infants with musculoskeletal computer models has allowed researchers to analyze muscle-to-muscle communication and whole-body sensations. Researchers have discovered patterns of muscle interaction that develop based on babies’ random exploratory behavior. A better understanding of how our sensorimotor system develops will not only help us gain insight into the origins of human movement, but also aid in the early diagnosis of developmental disorders.

If you’ve ever spent time with a baby, you’ve probably noticed that they rarely sit still. Shortly after birth; and even in the womb –; babies begin to kick, wiggle, and move without purpose or external stimulus. These are called “locomotor movements,” and researchers believe they play an important role in the development of the sensorimotor system—the ability to control muscles, movement, and coordination. A better understanding of how they are involved in early human development could also lead to the identification of early indicators of certain developmental disorders such as cerebral palsy.

Currently, there is limited knowledge about how newborns and infants learn to move.

Previous studies of sensorimotor development have focused on kinematic properties, that is, muscle activity that drives movement of joints and body parts. However, our study focused on whole-body muscle activity and sensory input signals. By combining musculoskeletal models and neuroscientific methods, we find that spontaneous movements that seem to have no clear task or purpose contribute to the development of coordinated sensorimotor development. ”

Specially Appointed Assistant Professor, Graduate School of Information Science and Technology Hoshinori Kanazawa

First, the team used motion capture technology to record the joint movements of 12 healthy newborns (less than 10 days old) and 10 infants (about 3 months old). They then used a full-body infant-scale musculoskeletal computer model they created to estimate the infant’s muscle activity and sensory input signals. Finally, they used computer algorithms to analyze the spatiotemporal (both spatial and temporal) features of the interaction between input signals and muscle activity.

“We were surprised to find that movements ‘wandered’ and pursued different sensorimotor interactions during spontaneous movements in infants. I named this phenomenon ‘sensory-motor wandering,'” says Kanazawa. “Generally, it has been thought that the development of the sensorimotor system depends on the repeated occurrence of sensorimotor interactions: the more you do the same action, the more likely you are to learn and remember it. However, our results suggest that infants develop their own sensorimotor systems, such as exploratory behavior and curiosity-based systems, so that they not only repeat the same behavior, but also repeat a variety of behaviors. In addition to this, our findings provide a conceptual link between early spontaneous movement and spontaneous neural activity.

Previous studies in humans and animals have shown that motor behavior (movement) involves a small set of primitive muscle control patterns. These are patterns commonly seen in task-specific and cyclic movements such as walking and reaching. The results of this latest study support the theory that neonates and infants can acquire sensorimotor modules—synchronized muscle activity and sensory input—through voluntary whole-body movements without a clear purpose or task. Even through sensorimotor wandering, babies showed increased coordinated whole-body movements and anticipatory movements. It showed a pattern and continuous movement.

Next, Kanazawa would like to examine how sensorimotor loitering, along with more complex behaviors and higher-order cognitive functions, affects subsequent development such as locomotion and reaching. “My original background is in infant rehabilitation. My major goal through my research is to understand the mechanisms underlying early motor development and find knowledge that can help facilitate infant development.” .”