Spontaneous movements of the baby are important for the development of a coordinated sensorimotor system

Spontaneous movements of the baby are important for the development of a coordinated sensorimotor system

Spontaneous movements of the baby are important for the development of a coordinated sensorimotor system

Abstract: A new study reveals the spontaneous, random movements of babies that help develop the sensorimotor system.

Source: University of Tokyo

Babies’ spontaneous, random movements help develop their sensorimotor system, according to new research conducted by the University of Tokyo.

Detailed recordings of the movements of newborns and infants were combined with a computer model of the musculoskeletal system to allow researchers to analyze the communication between muscles and sensations throughout the body.

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

A better understanding of how our sensorimotor system develops could help us gain insight into the origins of human movement, as well as in earlier 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 that they play an important role in the development of the sensorimotor system, that is, the ability to control muscles, movements and coordination.

If researchers can better understand these seemingly random movements and how they are involved in early human development, we may be able to 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, muscle activities that cause movement in a joint or part of the body,” said project assistant professor Hoshinori Kanazawa of the Faculty of Information Science and Technology.

“However, our study focused on muscle activity and sensory input to the whole body. By combining a musculoskeletal model and a neuroscientific method, we discovered 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 (about three months old) using motion capture technology. They then assessed the babies’ muscle activity and sensory input using a full-body musculoskeletal computer model of the infants they had built.

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

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

Spontaneous movements of the baby are important for the development of a coordinated sensorimotor system
Markers for the motion capture camera were gently applied to the baby’s limbs, head and abdomen, allowing the team to capture the full range of motion. Credit: 2022 Kanazawa et al.

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

“However, our results imply that infants develop their own sensorimotor system based on exploratory behavior or curiosity, so that they do not just repeat the same action, but different actions. In addition, our findings provide a conceptual link between early spontaneous movements and spontaneous neuronal activity.”

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

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

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

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

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

About this neurodevelopmental research news

Author: Press office
Source: University of Tokyo
Contact: Press Office – University of Tokyo
Picture: Image attributed to Kanazawa et al

Original research: Findings will appear in PNAS


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