Neural Circuit Effects of Ketamine in Depression

Inclusion Criteria: MDD Group * Male or female aged 18-65 years; * Ability for participant to comply with the requirements of the study as determined by the PI; * Capacity to provide informed consent; * Meets diagnostic criteria for current MDD according to the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5); * In a current major depressive episode (MDE) of at least moderate severity according to DSM-5; * Women must be using a medically accepted reliable means of contraception (if using an oral contraceptive medication, they must also be using a barrier contraceptive) or not be of childbearing potential (i.e., surgically sterile, postmenopausal for at least one year). * Women of childbearing potential must have a negative pregnancy test at screening and prior to the infusion. HC Group * Male or female aged 18-65 years; * Capacity to provide informed consent; * Women must be using a medically accepted reliable means of contraception (if using an oral contraceptive medication, they must also be using a barrier contraceptive) or not be of childbearing potential (i.e., surgically sterile, postmenopausal for at least one year). * Ability for participant to comply with the requirements of the study as determined by the PI; Exclusion Criteria: MDD Group * Current or history of schizophrenia or other psychotic disorder/episode, bipolar disorder, neurodevelopmental disorder, or neurocognitive disorder; * Current major depressive disorder with psychot…