The spontaneous movements of the baby are important for the development of the coordinated sensorimotor system.

Resume: A new study reveals that the spontaneous and random movements that babies make help in the development of the sensorimotor system.

Fountain: University of Tokyo

The spontaneous and random movements of the baby help the development of its sensorimotor system, according to new research led by the University of Tokyo.

Detailed motion capture of newborns and infants was combined with a musculoskeletal computer model to allow researchers to analyze communication between muscles and sensations throughout the body.

The researchers found developing patterns of muscle interaction based on the babies’ random exploratory behavior that would later enable them to make sequential movements as infants.

Better understanding how our sensorimotor system develops could help us better understand the origin of human movement, as well as previous 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 sensorimotor system, meaning the ability to control muscles, movement, and coordination.

If researchers can better understand these seemingly random movements and how they’re involved in early human development, we might also identify early indicators of certain developmental disorders, such as cerebral palsy.

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

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

First, the team recorded the joint movements of 12 healthy newborns (less than 10 days old) and 10 young infants (around three months old) using motion capture technology. Next, they estimated the infants’ muscle activity and sensory input signals with the help of a child-scale whole-body musculoskeletal computer model they had created.

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

“We were surprised that during spontaneous movement, the infants’ movements ‘wander’ and pursue various sensorimotor interactions. We call this phenomenon ‘sensorimotor wandering,’” Kanazawa said.

This shows a baby with its movements mapped.
The motion capture camera markers were gently applied to the baby’s limbs, head and belly, allowing the team to capture the full range of motion. Credit: 2022 Kanazawa et al.

“It has been commonly assumed that the development of the sensorimotor system generally depends on the occurrence of repeated sensorimotor interactions, which means that the more you do the same action, the more likely you are to learn and remember it.

“However, our results implied that babies develop their own sensorimotor system based on exploratory behavior or curiosity, so they do not just repeat the same action but a variety of actions. In addition to this, our findings provide a conceptual link between spontaneous first movements and spontaneous neural activity.”

See also

This shows the parents sleeping next to their baby.

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

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

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

Next, Kanazawa wants to see how sensorimotor ambulation affects later development, such as walking and reaching, along with more complex behaviors and higher cognitive functions.

“My original background is in child rehabilitation. My big goal through my research is to understand the underlying mechanisms of early motor development and find insights that help promote the development of the baby.”

About this neurodevelopmental research news

Author: press office
Fountain: University of Tokyo
Contact: Press Office – University of Tokyo
Picture: The image is attributed to Kanazawa et al.

original research: Findings will appear on PNAS

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