Healthy controls (HC) will be studied once to provide data needed to validate the virtual neuro-navigation system. All subjects will undergo a single MRI session and will then participate in an on-line neuro-navigation session in which various TMS coil positions will be recorded. The brain/head images will be provided to the programmer to permit development of the virtual neuro-navigation algorithm. Data from Yr1 will be used by the programmer as a training sample, and from Yr2 as a test sample.

HC subjects (n=10)/yr will be studied once to provide data needed to validate the virtual neuro-navigation system. All subjects will undergo a single Human Connectome Project compatible MRI session permitting application of both surface-based and more standard volumetric analyses. Subjects will then participate in an on-line neuro-navigation session in which TMS coil positions (in 10/20 coordinate space) will be recorded corresponding to the following targets: 1) hand-representation of motor strip; 2) 5-cm location; 3) 5.5 cm location; 4) MNI coordinates corresponding to the "Fitzgerald"4 and "Weigand"6 volumetric targets; 5) peak anti-correlated region (calculated from rsfcfMRI data alone); 6) center of our targeted parcel, calculated using surface-based approaches. The brain/head images will be provided to the programmer to permit development of the virtual neuro-navigation algorithm. Data from Yr1 will be used by the programmer as a training sample, and from Yr2 as a test sample. The Go/No-go criterion is an interclass correlation coefficient (ICC) of >.9 between scalp coordinates determined by on-line neuro-navigation and those determined virtually

Inclusion Criteria:

• Non-depressed subjects

Exclusion Criteria:

• Ever met criteria for a psychotic disorder (Sz, SzAff, Bipolar disorder); anorexia nervosa or bulimia nervosa within the last year
• Unstable medical condition by history, physical exam or laboratory results
• Contraindications to MRI (based on metal screening form)
• Meets criteria for claustrophobia
• Recent drug or alcohol use disorder with DSM-5 specifier of moderate or severe within 6 months, or mild within 2 months; lifetime history of IV drug use
• A neurological or neuromuscular disorder;
• Require medications for a general medical condition that contraindicate the TMS treatment
• History of ketamine treatment within 6 mo
• History of monoamine oxidase inhibitor (MAOI) within the past month
• Lacks capacity to consent
• Taking medications that increase the risk of seizures. For patients on permitted concomitant psychotropic agents (antidepressants, anticonvulsants, benzodiazepines, hypnotics, opiates, triiodothyronine (T3), modafinil, psychostimulants, buspirone, melatonin, omega-3 fatty acids, folate, lmethylfolate, s-adenosyl methionine, lithium) dosing must be stable for at least four weeks prior to study entry

Healthy Controls