Child NeuroDevelopment

- Neuro development in Children

Child Neurodevelopment - Learn about Neuro development in Children. Topics, Stages, prenatal, postnatal, birth, disorders, evaluation, clinic, hospital, neurodevelopmental therapy. - Find neuroscience, neurology and neurodevelopmental courses in universities and institutes.

Neurodevelopment in Children

Neural Development in Childs. Chronology of gross neural development from prenatal to postnatal stages.

Hows the nervous system grows?
In general, the Central Nervous System (CNS), the brain and spinal cord development is: head (cephalic) to tail (caudal), near (proximal) to far (distal), inferior (subcortical) to dorsal (cortical)

Neurodevelopment Stages. Prenatal Neurodevelopment, postnatal and child development. Timing of Events.
Development of neural tube.
Every neuron in nervous system generated in first trimester, with exception of tail of distribution of last layer of isocortex and external granular layer of cerebellum (hippocampal dentate gyrus and olfactory bulb neurons are generated throughout life.
Basic axonal pathways of brainstem laid down.
Migration of cells.
Differentiation of cells.
Basic wiring of brain (large patterns of connectivity between neural regions).
Connection of thalamus to all regions of isocortex- pattern of connections resembles adult pattern.
Intracortical pathways begin to be established.
Appearance of CC around 90 day gestation.
Apoptotic neuronal death (apoptotic suggests that it is organized cell death, not disorganized dissolution of the cell).
Activity-dependent self-organization of the nervous system- first motor activity of fetus begins.
Reciprocal connectivity from higher-order cortical areas to primary areas.
Initial myelination.
Large descending pathways from cortex- top-down connectivity with sensory and motor systems.
Synaptic connections between isocortex and related structures.

Order of development of the brain and the nervous system.
The brain develops from the neck-up, and the spinal cord develops from the neck-down, roughly in this order:
Brainstem (medulla, pons, midbrain, cranial nerves). Problems : crossed or lazy eyes, deafness, sleep disturbances, hallucinations, etc.
Cerebellum and basal ganglia. Problems : ataxia, involuntary movements, floppiness.
Limbic system (thalamus, hypothalamus, amygdala). Problems : ADD, emotional disorders, obesity, precocious puberty, etc.
Primary sensory input areas of the cortex. Problems : central auditory disorders.
Motor output areas of the cortex. Problems : incoordination, spasticity.
Association, integration, memory, and planning areas. Problems : ADD, LD, and others.
Alternate way of describing development:
Primary Zones: modality specific; fully functional by end of 1st year
Secondary zones: integrate modality-specific info into perceptive info. Become fully functional within first 5 years of life
Tertiary zones: associative, supramodal areas encompassing borders of parietal, temporal, and occipital zones as well as prefrontal region with its cortical and subcortical connections. Integrate info across modalities and control executive, purposive, and conative aspects of functioning. Become functional between ages 5 and 8, prefrontal somewhat later (maybe by age 12)

Prenatal Neurodevelopment Neural system development from 0 months to birth.

Prenatal Through Postnatal Processes

Myelination. Sensory areas myelinate before motor (may be responsible for comprehension/ production language disparity).
Myelination of callosal and associational cortical regions may continue into third and fourth decade of life.

Synaptogenesis

The synaptogenesis and synapse elimination co-occur over most of early postnatal development
Primary mode of learning in nervous system takes place when juncture is formed or modified as a function of experience
Synaptic connectivity is considered the primary means by which knowledge is represented in the brain
Generation of synapses in isocortex accelerates around birth; simultaneous peaking of synaptogenesis across all cortical areas
Brain suddenly starts to generate massive numbers of synapses just before environmental experience (ie, birth) in all regions associated with sensory, motor, motivational, and linguistic ability
Synapse generation overshoots by a substantial proportion in first six months, then declines to adult values
Five stages of synaptogenesis :
Synapses present in preplate,
Synapses generated in cortical plate,
Synaptogenesis synchronized in global perinatal burst,
Stabilized high level lasting from late infancy until puberty,
Synapses steadily decline in density and number from puberty through adulthood.

Birth

By birth all cells are generated.
all major incoming sensory pathways are in place and have gone through period of refinement of total cells, connections, and topographic organization.
intracortical and connectional pathways well developed (output pathways lag).
microstructure of features such as motion and orientation in visual system present.
Big cortical regions (primary sensory and motor) have adult input and topography.

Postnatal NeuroDevelopment

Brain weight at birth is 25% of adult weight; about 80% by age 2 years.
Brain weighs b/w 300-350 g and grows rapidly, reaching 80% of adult weight at 4 yrs.
Cortical surface area of hemispheres doubles, reaching adult dimensions by age 2.
Increase in brain size inferred from head circumference.
Growth of brain due to increase in size, complexity, and myelination (rather than number) of nerve cells.
Primary sensory and motor areas are most advanced, followed by progressive development of adjacent sensory association areas, and finally parietal and temporal association areas.
Prefrontal lobes least developed at birth, not much development until after second year.
Functional organization of nervous system reflecting increased responsiveness to environmental stim.
Functional elaboration of association fibers and tracts; increasing connectivity.
EEG changes - after birth irregular and low amplitude; by 4 months of age, first slow rhythm (3-4 discharges per second) becomes evident, primarily over occipital cortex; frequency of EEG discharge increases over tie until characteristic stable alpha rhythms (11-12 per second) is attained.
Maturation of the Cortex in Early Postnatal Period. Neurogenesis begins at front edge of cortex where frontal cortex abuts inferotemporal cortex and proceeds back to primary visual cortex.
Primary sensory nuclei in thalamus, including ventrobasal complex (somatosensory), medial geniculate body (auditory), and lateral geniculate body (visual) generated first and establish axonal connections to cortex first.
Nuclei that innervate frontal, parietal, and inferotemporal cortex are last.
Influences by the genetic propensities of child and family, child’s physiology (metabolism, nutrition, hormone and neurotransmitter and immune activity, toxins, infections), child’s physical environment (birth trauma, head injury, physical shelter and dangers), child’s psychosocial environment (family, peers, school, community, culture). Child’s biology, in turn, influences psychosocial environment.
Growth of axons. Problems and abnormal connections.
Increase complexity of dendrites and axons on each neuron. Problems are sparse, skinny dendrites or fewer receptors.
Formation of synapses between neurons, or with muscle cells. If the link isn’t active it dies or moves away.
Death of unused synapses and neurons. Problems like persisting nonfunctional cells make abnormal connections or develop other problems (e.g., seizures, tumors).
Myelination of axons. Problems like weak or absent communication between brain areas, or between brain and muscles.
Cell populations mature through developmental stages at different times and in different regions of the brain. Stages are: proliferation, migration, differentiation, myelination, cell death.

Miscellaneous NeuroDevelopmental Issues

Effects of brain injury tend to be less specific in children than adults, particularly if damage incurred before age 5-7 years

Frontal functions develop in a step-wise fashion with some functions developed by about 6-7 years of age and others continuing to mature into adolescence.

Phenotypic Variation. Children with a particular brain disorder rarely show a specific, unique pattern of behavior. Effects of brain disorders vary with nature of the brain insult, environmental support and stress; sex and handedness; age at time of injury; age at time of outcome measurement; and nature of the outcome measures (Fletcher, Yeates, Taylor, Dennis, Shapiro, Satz, Baron, etc., etc.)

Aging

Aging - Cerebral Institute of Discovery - Neurotransmitters and Symptoms of aging. An overview of aging and of aging theories. Evolution theory and species-specific aging. Sex and aging. Aging of other organ systems The free radical theory of aging. Mitochondria and aging. The glycation theory of aging. Proteins damage and maintenance in aging. Dna damage and DNA repair. Telomeres and aging. Cellular senescence and apoptosis in aging. Accelerated aging diseases (segmental progeria). Longevity genes (flies & worms). Menopause and age. Longevity genes (mammals). Sirtuins and deacetylases in aging. Hormones and aging. The immune system and aging. Inflammation and aging. Accumulation of toxins and chemical garbage. Cancer and aging. Biomarkers of aging. Caloric restriction with adequate nutrition (cran). Other methods to slow aging. Regenerative medicine, stem cells and rejuvenation. Aging: cause & cure, books, references, summary & conclusions.

What is a Neurodevelopmental Pediatrician? A neurodevelopmental pediatrician is a medical professional specialized in neurodevelopment for childs.

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