For the formation of imprinting in birds, protein synthesis is known to be essential in the medial hyperstriatum ventrale (MHV) of the forebrain after presentation of an imprinting stimulus. We have searched for the genes whose expressions are increased in duckling's MHV during formation of imprinting, and identified kainate-binding protein and calmodulin genes. This may reflect the formation of glutamatergic pathways in MHV.