Mj. Litzinger et al., REGIONAL DIFFERENCES IN THE CRITICAL PERIOD NEURODEVELOPMENT IN THE MOUSE - IMPLICATIONS FOR NEONATAL SEIZURES, Journal of child neurology, 9(1), 1994, pp. 77-80
The voltage-sensitive calcium channel probe I-125-omega-GVIA conotoxin
has been shown to be a developmental marker in whole brain preparatio
ns of Swiss Webster mice. The present study looks more carefully at re
gional dissections of the mouse brain (cerebrum, cerebellum, and brain
stem) at postnatal day 8 and postnatal day 16. I-125-omega-GVIA. cono
toxin binding, thought to be presynaptic, showed a dramatic increase b
etween postnatal days 8 and 16 in the cerebral cortex, a decrease in t
he cerebellum, and no change in the brain stem. The dramatic cerebral
cortex increases indicated by these binding data correspond to a criti
cal period between postnatal day 11 and postnatal day 14 in Swiss Webs
ter mice; during this critical period, dendrites exhibit rapid outgrow
th, sensory modalities come on line, electroencephalographic patterns
mature, and the cortex reaches adult proportions. This period parallel
s a similar initiation of electrical maturation in the 28- to 32-week
neonatal human brain. We conclude from these data that the unusual cli
nical presentation of neonatal seizures is not just the result of imma
ture myelin formation. It includes incomplete synapse formation linkin
g the cortex to the brain stem.