The purpose of this study is to evaluate the effects of TS-134 on ketamine-induced BOLD signals in ROIs in resting fMRI in healthy adult subjects.

Inclusion Criteria:

• Healthy adult male and female subjects between 18 and 55 years of age inclusive (at the time of initial informed consent)
• Body weight ≥ 45 and ≤ 87 kg
• Body Mass Index (BMI) ≥ 18 and ≤ 30 kg/m2

Exclusion Criteria:

• Female subjects who are pregnant, intend to become pregnant, or are breastfeeding
• History or presence of psychiatric or neurologic disease or condition
• History of first-degree relative with schizophrenia or mood disorder with psychosis
• History of alcohol or drug abuse
• History of recreational ketamine use, recreational PCP use, or an adverse reaction to ketamine
• History of violence
• Presence or positive history of significant medical illness, including high blood pressure, low blood pressure or orthostatic hypotension
• Any subjects who show subthreshold ketamine BOLD response
• Metal implants, pacemaker, other metal or paramagnetic objects contained within the body
• Claustrophobia
• Subject with any history of suicidal behavior or is currently at risk of suicide in the opinion of the investigator