ABSTRACT
<p><b>OBJECTIVE</b>To investigate the growth and development of brain derived neurophic factor(BDNF)-positive neurons in the frontal lobe of human fetus.</p><p><b>METHODS</b>The expression of the BDNF-positive neurons in the frontal lobe of human fetus in the 2(nd),3(rd),and 4(th) month of gestation were observed with the streptavidin-biotin-complex/immunoperoxidase(SABC)method.</p><p><b>RESULTS</b>By the second month of gestation,BDNF-positive neurons were seen in the subventricular layer of the frontal lobe of cerebellum.By the third month of gestation,BDNF-positive neurons in the central layer were in various shapes,with big nucleus,less cytoplasm,and small processes.By the fourth month of gestation,BDNF-positive neurons in the central layer grew larger in size,cytoplasm increased,the BDNF-positive expression was enhanced with deeper dyeing,and the nerve fibers and particles were distributed between neurons;also,the BDNF-positive neurons were seen in the marginal layer of the frontal lobe of cerebrum.</p><p><b>CONCLUSION</b>BDNF-positive neurons may participate in the early development of the frontal lobe of cerebrum of human fetus.</p>