A baby’s spontaneous movements are important for the development of the coordinated sensory system

summary: A new study revealed that the spontaneous and random movements of children help in the development of the sensory system.

Source: University of Tokyo

Children’s automatic and random movements help develop their sensory system, according to new research led by the University of Tokyo.

Detailed motion capture of newborns and infants was combined with a computer model of skeletal muscles to enable the researchers to analyze muscle communication and sensation across the whole body.

Researchers have found patterns of muscle interaction that develop based on children’s random exploratory behavior that will later enable them to perform sequential movements as children.

A better understanding of how our sensory system evolved can help us gain insights into the origins of human movement as well as early diagnoses of developmental disorders.

From birth – and even in the womb – babies begin to kick, wiggle and move seemingly without purpose or external stimulation. These are called “spontaneous movements,” and researchers believe they have an important role to play in the development of the sensory system, that is, the ability to control muscles, movement, and coordination.

If researchers can better understand these seemingly random movements and how they are involved in early human development, we might also be able to identify early indicators of specific developmental disorders, such as cerebral palsy.

Currently, there is limited knowledge about how newborns and infants learn to move around. “Previous research in the area of ​​sensory development has focused on kinematic properties, the muscle activities that cause movement in a joint or part of the body,” said project associate professor Hoshinori Kanazawa of the Graduate School of Information Science and Technology.

However, our study focused on muscle activity and whole-body sensory input signals. By combining a musculoskeletal model with a neuroscience method, we found that spontaneous movements, which appear to have no clear mission or purpose, contribute to coordinated sensory development.”

First, the team recorded the joint movements of 12 healthy newborns (less than 10 days old) and 10 young infants (about three months old) using motion capture technology. Next, they estimated the children’s muscle activity and sensory input signals with the help of a full-body-scale computer model of skeletal muscles, which they created.

Finally, they used computer algorithms to analyze spatiotemporal features (both space and time) of the interaction between input signals and muscle activity.

“We were surprised that during spontaneous movement, the babies’ movements ‘wandered’ and tracked different sensory interactions. We named this phenomenon sensorimotor fugue,” Kanazawa said.

“It is commonly assumed that the development of the sensorimotor system is generally based on the occurrence of repeated sensory interactions, which means that the more often you perform the same action, the more likely it is to learn and remember it.

However, our results suggest that infants develop their sensorimotor system based on exploratory behavior or curiosity, so they not only repeat the same action, but a variety of actions. In addition, our findings provide a conceptual link between early spontaneous movements and automatic nervous activity.”

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Previous studies in humans and animals have shown that locomotor behavior (movement) involves a small set of primitive muscle control patterns. These are patterns that can usually be seen in specific or periodic movements, such as walking or reaching.

The results of this latest study support the theory that newborns and infants can acquire sensory units, that is, synchronized muscle activities and sensory input, through spontaneous whole-body movements without an explicit purpose or task.

Even through sensory wandering, the infants showed an increase in coordinated whole-body movements and in anticipatory movements. The movements made by the infant group showed more common sequential patterns and movements, compared to the random movements of the newborn group.

Next, Kanazawa wants to look at how kinesthetic wandering affects later development, such as walking and reaching, along with more complex behaviors and higher cognitive functions.

“My original background is infant rehabilitation. My big goal with my research is to understand the basic mechanisms of early motor development and to find knowledge that will help enhance child development.”

About this research on neurodevelopmental news

author: press office
Source: University of Tokyo
communication: Press Office – University of Tokyo
picture: Image credit to Kanazawa et al

Original search: Results will appear in PNAS