Spontaneous baby movements are important for the development of a coordinated sensorimotor system
Overview: A new study reveals the spontaneous, voluntary movements babies make as they develop the sensorimotor system.
Source: University of Tokyo
Spontaneous, voluntary baby movements help develop their 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 the communication between muscles and sensations throughout the body.
Researchers discovered patterns of muscle interaction that developed based on the babies’ random exploratory behavior, allowing them to perform sequential movements later on as babies.
A better understanding of how our sensorimotor system develops can help us understand the origins of human movements and 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 they play an important role in the development of the sensorimotor system, i.e. the ability to control the muscles, movements and coordination.
If researchers can better understand these seemingly random movements and how they are involved in early human development, we may also 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 Graduate School of Information Science and Technology.
“However, our research focused on muscle activity and sensory input signals for the whole body. 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 babies (around three months old) using motion capture technology. They then estimated the babies’ muscle activity and sensory input signals using a computer model of the baby-scale musculoskeletal system they created for the whole body.
Finally, they used computer algorithms to analyze the spatiotemporal (both space and time) characteristics of the interaction between the input signals and muscle activity.
“We were surprised that during spontaneous movements, babies’ movements ‘wandered off’ and emulated different sensorimotor interactions. We called this phenomenon ‘sensory-motor wandering,'” Kanazawa said.
“It is generally accepted 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 implied that infants develop their own sensorimotor system based on exploratory behavior or curiosity, so they repeat not just the same action, but a variety of actions. In addition, our findings provide a conceptual link between early spontaneous movements and spontaneous neuronal activity. “
Previous studies in humans and animals have shown that motor behavior (movement) involves a small number of primitive muscle control patterns. These are patterns typically seen in task-specific or cyclic movements, such as walking or reaching.
The results of this latest study support the theory that newborns and infants can acquire sensorimotor modules, i.e., synchronized muscle activities and sensory inputs, through spontaneous whole-body movements without an explicit goal or task.
Even through sensorimotor wandering, the babies showed an increase in coordinated whole-body movements and in anticipatory movements. The movements performed by the infant group showed more general 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 behaviors and higher cognitive functions.
“My original background is in infant rehabilitation. My big goal with my research is to understand the underlying mechanisms of early motor development and to find knowledge that can help promote the development of babies.”
About this neurological research news
Original research: The findings appear in PNAS
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