Summary: A new study reveals that spontaneous and random movements of babies contribute to the development of the sensory-motor system.
Source: University of Tokyo
According to a new study conducted by the University of Tokyo, the baby’s spontaneous and random movements promote the development of its sensorimotor system.
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.
The researchers found patterns of muscle interaction developing on the basis of babies’ random exploratory behavior that would later allow them to perform sequential movements as infants.
A better understanding of the development of our sensory-motor system could help us better understand the origin of human movement as well as early diagnoses of developmental disorders.
From birth – and even in the womb – babies begin to kick, squirm 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-motor system, i.e. 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 certain developmental disorders, such as cerebral palsy.
Currently, knowledge about how newborns and infants learn to move is limited. “Previous research on sensorimotor development has focused on kinematic properties, the muscular activities that cause a joint or body part to move,” said project assistant professor Hoshinori Kanazawa of the Graduate School information science and technology.
However, our study focused on muscle activity and sensory input signals for the whole body. By combining a musculoskeletal model and a neuroscientific method, we discovered that spontaneous movements, which seem to have no explicit task or purpose, contribute to coordinated sensorimotor development.
First, the team recorded the joint movements of 12 healthy newborn babies (under 10 days old) and 10 young infants (about three months old) using motion capture. Next, they estimated the babies’ muscle activity and sensory input signals using an infant-scale whole-body musculoskeletal computer model they had created.
Finally, they used computer algorithms to analyze the spatio-temporal characteristics (both spatial and temporal) of the interaction between input signals and muscle activity.
We were surprised to find that during spontaneous movements, the infants’ movements “wandered” and they pursued various sensorimotor interactions. We named this phenomenon “sensorimotor wandering,” Kanazawa said.
“It has been commonly accepted that the development of the sensory-motor system generally depends on the occurrence of repeated sensory-motor interactions, which means that the more you do the same action, the more likely you are to learn it and remember it.
However, our findings imply that infants develop their own sensorimotor system based on exploratory behavior or curiosity, such that they do not simply repeat the same action, but a variety of actions. In addition to this, our findings provide a conceptual link between early spontaneous movements and spontaneous neural activity.
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Previous studies in humans and animals have shown that motor behavior (movement) involves a small set of primitive muscle control patterns. These are patterns that can usually be seen in task-specific or cyclical movements, such as walking or reaching.
The results of this latest study support the theory that newborns and infants can acquire sensory-motor modules, i.e. synchronized muscle activities and sensory inputs, through spontaneous whole-body movements. without an explicit goal or task.
Even through sensorimotor wandering, babies showed increased 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 examine how sensorimotor wandering affects later development, such as walking and reaching, as well as more complex behaviors and higher cognitive functions.
“My initial training is in child rehabilitation. My big goal through my research is to understand the underlying mechanisms of early motor development and to find insights that will help promote baby development.
About this neurodevelopment research news
Author: Press office
Source: University of Tokyo
Contact: Press Office – University of Tokyo
Image: Image is credited to Kanazawa et al
Original research: The findings will appear in PNAS
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