This 2015 New York rodent study provided further details on the production of new neurons in the adult hippocampus. The researchers found that a protein that regulated a glutamate receptor also:
“Significantly influences hippocampal neurogenesis and that both the proliferation and survival of newborn neurons are impaired in the absence.”
The study showed:
“The effect of Norbin [the protein] on neurogenesis is likely caused by a nonautonomous niche effect.
These results show that Norbin is a regulator of adult hippocampal neurogenesis and that its deletion causes depressive-like behaviors.”
http://www.pnas.org/content/112/31/9745.full “Norbin ablation results in defective adult hippocampal neurogenesis and depressive-like behavior in mice”