On p. 402 of the April 2000 issue, “Embryonic stem cell lines from human blastocysts: somatic differentiation in vitro,” by Benjamin E. Reubinoff, Martin F. Pera, Chui-Yee Fong, Alan Trounson, and Ariff Bongso, the following sentences were incorrectly written: “These differentiated cells displayed morphology and expression of structural markers characteristic of mature neuronal differentiation, such as the 200 kDa neurofilament proteins and β-tubulin (Fig. 6B, H). Moreover, the differentiated cells expressed specific markers of mature neurons such as the 160 kDa neurofilament proteins (Fig. 6C), Map2a + b (Fig. 6D), synaptophysin (Fig. 6F), and β-tubulin (Fig. 6H). Finally, the cultures contained cells that synthesized glutamate (Fig. 6E), and expressed the rate-limiting enzyme in GABA biosynthesis (glutamic acid decarboxylase, Figs 3C and 6G), as well as receptor subunits for this latter neurotransmitter (GABAAα2-receptor subunit, Fig. 3D).