Why does a newborn shiver frequently at 4 days old?

Patient's question:

Patient Age: Newborn, 4 days
Condition Description: Newborn, 4 days, legs frequently tremble, the duration of trembling is about 1 minute.
Treatment History and Effect: The doctor at the community health center did not provide a treatment plan.
Desired Help: What is the cause? Where can it be treated?

Doctor's answer:

Hello, for newborns experiencing this, it is a physiological phenomenon. This is because the nervous system of the baby is not yet fully developed. When exposed to environmental sound stimuli, the neural impulses are transmitted to the brain but cannot be localized in the cerebral cortex. As a result, the stimulus waves spread to the nerve fibers in the limbs, causing movements and tremors in the limbs.
Around 3-4 months of age, as the baby's nervous system function gradually matures, this phenomenon will gradually disappear. Therefore, there is no need to worry too much. When the baby startsleams, gently pressing on any part of his body will help calm him down.