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The development of the nervous system in humans, or neural development, or neurodevelopment involves the studies of embryology, developmental biology, and neuroscience. These describe the cellular and molecular mechanisms by which the complex nervous system forms in humans, develops during prenatal development, and continues to develop postnatally.
The 3 ′ (3 prime end) genes in the Hox cluster are induced by retinoic acid in the hindbrain, whereas the 5 ′ (5 prime end) Hox genes are not induced by retinoic acid and are expressed more posteriorly in the spinal cord. Hoxb-1 is expressed in rhombomere 4 and gives rise to the facial nerve.
Cortical white matter increases from childhood (~9 years) to adolescence (~14 years), most notably in the frontal and parietal cortices. [8] Cortical grey matter development peaks at ~12 years of age in the frontal and parietal cortices, and 14–16 years in the temporal lobes (with the superior temporal cortex being last to mature), peaking at about roughly the same age in both sexes ...
Physical development. Typically grows between 0.5 and 0.75 inches (1.3 and 1.9 cm) and gains between 1 and 1.25 pounds (450 and 570 g) Motor development. Able to push up to a crawling position and may be able to rock on knees. [31] Able to sit with support. [31] Able to stand with help and bounce while standing. [31]
In a normal infant, the palmar grasp reflex is present during the first three months of age and disappears by six months of age. Disappearance of the reflex has been attributed to conscious and voluntary hand use. [3] Based on collected evidence, there is no significant difference between the reflexes of normal-term and pre-term infants. [2] [3]
The child's nonverbal communication of how they are feeling is seen in babies 0 to 3 months who use wild, jerky movements of the body to show excitement or distress. [127] This develops to more rhythmic movements of the entire body at 3 to 5 months to demonstrate the child's anger or delight. [127]
Synaptic pruning, a phase in the development of the nervous system, is the process of synapse elimination that occurs between early childhood and the onset of puberty in many mammals, including humans. [1] Pruning starts near the time of birth and continues into the late-20s. [2]
The Moro reflex is an infantile reflex that develops between 28 and 32 weeks of gestation and disappears at 3–6 months of age. It is a response to a sudden loss of support and involves three distinct components: [1] spreading out the arms ; pulling the arms in ; crying (usually) It is distinct from the startle response. [2]