The brain is one of the most complex organs of the body.  At birth the full term infant's brain weighs ~ 330 grams and has its full complement of brain cells.  The neonate's brain is highly susceptible to insult, and once damaged, the cells will not recover.  Incidents such as asphyxia, metabolic disturbances, maternal illnesses, or infections, maternal or neonatal, can lead to permanent neurological damage and dysfunction.  The neurologic defects may be extensive involving the brain, spinal cord, and surrounding bone and skin, or relatively minor, with a gradually improving neurological status.  When attempting to determine underlying cause attention must focus on both prenatal and perinatal events.  Details of events occurring during the early weeks of gestation are as important as events occurring during the labor & delivery or neonatal period.  During the 3rd-5th weeks of gestation the neural tube is developing and disruption of normal neural development may lead to a variety of defects ranging from minor to severe in nature.  Myelomeninogocele or anencephaly are just two examples of the type of defects that may occur if there is disruption in normal neural tube development.  Traumatic injuries or asphyxial episodes may be associated with difficult deliveries while prolonged labor or premature rupture of the membranes may be associated with sepsis.  Either of these may place the neonate's still developing CNS at risk for temporary or permanent neurologic dysfunction.  Finally, asphyxial episodes, sepsis, and/or prematurity, as well as the associated neonatal complications, continue to place the infant at risk even after delivery.