Since chronic antidepressant treatment or exercise upregulates Nptx2 expression in the hippocampus [1, 13] and Nptx2-deficient mice display more c-Fos-positive cells in the DG and CA3 regions but not the amygdala after acute stress, we hypothesized that hippocampal Nptx2 modulates anxiety behavior. This evidence concerns the gene FOS and Anxiety.