The present study examined developmental differences in event-related potentials between second graders and adults in arithmetic. Consistent with previous literature in adults, multiplication for both children and adults produced a greater left anterior negativity from 400 to 900 msec, whereas addition produced a greater right posterior negativity from 400 to 900 msec. Adults showed larger left anterior negativities in the time window suggesting that adults rely more than children on a verbal processing system for solving these problems. Children showed larger right posterior negativities in the time window suggesting that they rely more on quantitative manipulation for solving these problems.

Stereoselective synthesis of cis-decalin structures using [4 + 2] cycloaddition is challenging. We explored the biosynthetic pathway of the fungal natural product fischerin (1) to identify a new pericyclase FinI that can catalyze such a reaction. The cocrystal structure of FinI, a predicted O-methyltransferase, with the product and SAM provides insight into cis-decalin formation in nature.