Male and female Carf wildtype (WT) and knockout (KO) adult mice (McDowell et al. 2010 (link)) or pups with their mothers at postnatal day 14 (P14) were transferred from their normal housing room with a 12 hr:12 hr light:dark cycle into a light-tight dark housing room to maintain constant darkness for 7 days. Animals in the unstimulated (dark) condition were killed and their eyes enucleated in the dark prior to bringing the body into the light to dissect the brain. Animals in the stimulated (light-exposed) condition were removed from the dark room and exposed to normal lighting for 6 hrs prior to tissue harvesting. For MK-801 (Sigma) experiments, 6-month-old adult were injected intraperitoneally (i.p.) in the dark with either saline (control) or 1mg/kg MK-801 diluted in 0.9% NaCl 30 min prior to being brought into the light. V1 visual cortex and S1 somatosensory cortex were isolated based on anatomical landmarks and immediately flash frozen. RNA and protein were harvested and measured as described above.