major stages of human brain development and related defects
DESCRIPTION
Simplified neuro embryologyTRANSCRIPT
Major Stages of Human Brain Development and Related Defects
Occurrence
Time (Weeks) Stage of Human Development Major Events
Major Anomalies
during Stage
3-4 Neurulation Notochord
Neural Plate Differentiation of
Brain into
Prosencephalon,
Mesencephalon &
Rhombencephalon
Anencephaly
Exencephaly
Arnold Chiari
Malformation
Meningocele
Meningomyelocoele
Myeloschisis
Neural Tube
Neural Crest
cells
Spinal Cord
Dura
4-7 Caudal Neural Tube Formation Canalisation followed by regressive differentiation Spina Bifida Occulta
5-6 Ventral Induction
(prosencephalon development)
Precordial Mesoderm Formation of Face & Forebrain Dermal Sinus
Prosencephalon
Cleavage of prosencephalon into
cerebral vesicles in the form of 2
cerebral hemispheres at 33 days
Faciotele cephalic
malformations
Occurrence
Time (Weeks) Stage of Human Development Major Events
Major Anomalies
during Stage
8-16 Neuronal Proliferation
Cellular Proliferation in the
ventricular &
subventricular zones
Differentiation of the Hypothalamus
Microencephaly
Macroencephaly
Optic Vesicles
Olfactory Bulbs & Tracts
1st fibres in Internal Capsule at 41
days
Thalamus & Basal Ganglia
Proliferation of the vascular tree, particularly venous
Interkinetic Nuclear Migration
12-20 Migration
Radial Migration in
Cerebrum (completed by 5
months)
Cortical Lamination
Schizencephaly
Agenesis of the
Corpus Callosum
Hirsprung disease
Radial tangential migration
in Cerebellum (completed
by 1 yr postnatally)
Occurrence
Time (Weeks) Stage of Human Development Major Events
Major Anomalies
during Stage
24-Postnatal Organisation
Late Neuronal Migration in Cerebrum & Cerebellum.
Mental Retardation
Down Syndrome
Perinatal Insults
Alignment, Orientation & Layering of Cortical neurons
Development of Synaptic contacts
Proliferation of Gila & Differentiation
Peak at Birth to
yrs Postnatal Myelination
Bulbospinal Tracts (24 weeks to postnatal)
Cerebral White
Matter Hypoplasia
Motor Roots (24 weeks to postnatal)
Medial Leminiscus (24 weeks to postnatal)
Pyramidal Tract (38 weeks to 2 yrs postnatal)
Frontopontine Tract (7-8 months postnatal to 2 yrs)
Corpus Callosum (4 months postnatal to 16 yrs)