Toward modeling the human nervous system in a dish: recent progress and outstanding challenges.

Studying the cellular and molecular bases governing development, and normal and abnormal functions of the human CNS is hampered by its complexity and the very limited possibility of experimentally manipulating it in vivo. Development of 3D, tissue-like culture systems offers much promise for boosting our understanding of human neural development, birth defects, neurodegenerative diseases and neural injury, and for providing platforms that will more accurately predict efficacy of putative therapeutic compounds and assess responses to potentially neurotoxic agents. Although novel technological developments and a more interdisciplinary approach to modeling the human CNS are accelerating the pace of discovery, increasing the complexity of in vitro systems increases the ordeals to be overcome to establish highly reproducible models amenable to quantitative analysis.