ENVIRONMENTAL AND GENETIC-DETERMINANTS OF NEURAL MIGRATION AND POSTMIGRATORY SURVIVAL

The study of genetic/epigenetic/environmental factors underlies all th erapeutic and preventive approaches in fetal, perinatal and paediatric neurology, including rehabilitation (3). In this paper, we selected a few targets of environmental determinants of brain development leadin g to underlying priorities for protection of the developing brain. Pre paration of the neural germinative epithelium has to be protected agai nst noxious pharmacological agents. New tools have been developed to i mprove early neural teratology, including the whole-embryo culture met hod. The neopallial astrocytic precursors have a dual origin. Astrocyt es of the white matter and deep neocortical layers derive from transfo rmed radial glial cells, whereas astrocytes of the upper neocortical l ayers derive from astrocytic precursors that migrate from the late ger minative zone after the end of neuronal migration. Among numerous fact ors able to interfere with these gliogenetic events an the control fac tors of the lysosomal and autophagic functions, interfering with radia l glial cell transformation into astrocytes. All lesions interrupting the migratory corridors of late astroglial migration can produce cytoa rchitectonic disturbances of the neocortical supragranular layers, wit h long-term consequences. The developing brain is weltering in a compl ex mixture including newly recognized excitotoxic substances, cytokine s and growth factors. These substances are sometimes environmental fri ends like maternal vasointestinal peptide, which prevents brain intrau terine growth retardation. They are sometimes excellent endogenous fri ends like neurotrophic excitatory agents in physiological conditions. They become often dangerous killers triggered by environmental signals like hypoxias/ischaemias and toxins produced by intrauterine infectio ns, launching the excitotoxic cascade. In this paper, we reviewed main ly environmental determinants interfering with neural cytogenesis and histogenesis during the embryonic, fetal and neonatal span of early li fe.