Fig. 4. Evaluation of scores obtained for immediate digit recall showed that S (+)- (P = 0.010) or R (−)-ketamine (P = 0.020) induced less impairment in digit recall than racemic ketamine at 1 min after drug injection. Bars report the mean ± SD. *Significant difference between racemic ketamine and S (+)-ketamine. †Significant difference between racemic ketamine and R (−)-ketamine.