DCS treatment: DCS can have opposing effects at low dose vs. high dose. In mouse cerebellar tissue there is an inverted U-shaped dose-response relationship. At low DCS concentrations, agonist activity may reflect binding to NMDA receptor (NMDAR) subunits. In contrast, at higher DCS concentrations antagonist effects may become prominent. Consistent with the above research, in both animal models and clinical applications, isolated low dose DCS treatments appear to have significant advantages over chronic treatment at higher doses. In animal models, a single dose of DCS reversed cognitive impairment produced by hippocampal lesions, anticholinergic agents, and early social deprivation. In healthy animals, a single dose of DCS enhanced extinction of conditioned fear performance on maze tasks, and visual recognition memory. Mice treated with a single, low-dose of DCS 24 or 72 hours after TBI exhibited significantly more rapid and complete recovery of motor and memory function compared with untreated controls. Tachyphylaxis rapidly develops with repeated dosing of DCS. A single dose of DCS administered within 30 minutes of extinction training increases 24 hour retention of fear extinction approximately 3-fold, whereas this effect was completely attenuated by 5 doses of DCS administered over 10 days preceding the extinction training.