Corrections and clarifications.
In the Research News article "Pot, heroin unlock new areas for neuroscience" by Marcia Barinaga (18 Dec., p. 1882), the diagram of the molecule anandamide on page 1883 was incorrect. The correct structure appears on page 1948 of the same issue, in figure 1A of the report "Isolation and structure of a brain constituent that binds to the cannabinoid receptor" by W. A. Devane et al. (p. 1946).