A Study To Examine The Effects Of PF-04958242 On Ketamine-Induced Cognitive Impairment In Healthy Volunteers

Inclusion Criteria: * Healthy male subjects 21 - 45 years old. * Able to read and write English as primary language. * Subjects who are willing to comply with study procedures. Exclusion Criteria: * History of any substance abuse or dependence disorder meeting DSM-IV criteria and/or by SCID-NP within the past 12 months, with the exception of nicotine. * Known sensitivity to ketamine * Any history of DSM-IV Axis I psychiatric disorders, determined by SCID-NP interview or diagnoses in the view of the investigator.