Fig. 4. Ketamine improved immobility during the forced swim test. Rats after spared nerve injury (SNI) demonstrated increased immobility during the forced swim test, compared with sham-operated rats. *P < 0.05, Student t  test. n = 6. For rats that had SNI for 14 days, ketamine (10 mg/kg) treatment improved immobility compared with saline treatment. *P < 0.05, Student t  test. Sham: n = 9; SNI: n = 11.