Some landmarks of embryonic neural development include the birth and differentiation of neurons from stem cell precursors, the migration of immature neurons from their birthplaces in the embryo to their final positions, outgrowth of axons from neurons and guidance of the motile growth cone through the embryo towards postsynaptic partners, the generation of synapses between these axons and their postsynaptic partners, and finally the lifelong changes in synapses which are thought to underlie learning and memory.
Human brain development
Highly schematic flowchart of human brain development.
The relationships between the age of the traumatized child, vulnerability and subsequent adverse sequelae are predicted by another key principle of neurodevelopment -- critical and sensitive periods.
As important in neurodevelopment as the pattern, quantity and quality of the neurochemical signals which neurons receive is the timing of signals.
Only then can the relationships between neurodevelopment and trauma-related neuropsychiatric problems be understood well enough to guide innovative therapeutic approaches and initiate social policy changes to bring an end to the war on children.
The median concentration of PCB 153 in the 10 studies ranged from 30 to 450 ng/g serum lipid, and the median of the 10 medians was 110 ng/g.
Because a direct laboratory-based comparison of exposure levels across all studies was not possible, we expressed the PCB levels from studies of neurodevelopment in a uniform manner using a combination of data from original investigators, laboratory reanalyses, calculations based on published data, and expert opinion.
Investigators from each study of PCBs and neurodevelopment of which we were aware (Table 1) contributed to this study and agreed on a protocol for parallel presentation of data.
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