As it is possible to regain a state of plasticity and reverse cognitive deficits by manipulating the onset and closure of ‘critical periods’ (Bradbury et al., 2002; Pizzorusso et al., 2002, 2006), regulating MMP-9 activity during CPP may aid in further development of precise and targeted treatments for neurodevelopmental disorders. The gene discussed is MMP9; the disease is neurodevelopmental disorder.