Similar to the hippocampal response, a deficit of brain-derived neurotrophic factor (BDNF), which emulates the response to chronic stress and is considered to be a candidate mechanism of depression, also led to increased expression of GluN1, GluN2A and GluN2B mRNA in the frontal cortex during the early stage of development [153]. This evidence concerns the gene BDNF and depressive symptom measurement.