The following database is built using Affymetrix's gene-chip 11K probe sets. We screened 11,000 genes and found 1,926 genes which exhibited dynamic changes. Self-organizing maps algorithm (SOM) was used to group the 1,926 genes and ESTs into 16 clusters based on similar expression dynamics over five time points (from embryonic day 16 to postnatal day 30) during the development of the mouse hippocampus. The label at the upper-left corn of each inset represents cluster numbers (from C0-C15). The number in the top center of each inset represents the number of genes in that particular cluster. The five dots in each inset represent the five developmental time points: E16, P1, P7, P16, and P30.