Noninvasive VNS to Facilitate Excitability in Motor Cortex

Inclusion Criteria: * Age 18-80 * endorsing good health Exclusion Criteria: * no TMS-induced motor cortex excitability changes in response to 20Hz motor cortex rTMS * active psychiatric or neurological disorders * history of CNS disease, concussion, overnight hospitalization, or other neurologic sequelae, tumors, seizures, frequent or severe headaches * metal implanted above the neck * currently taking seizure reducing medications * currently taking psychotropic medications * any psychotropic medication taken within 5 half-lives of procedure time * abuse or dependence of drugs (excluding nicotine and caffeine) * currently taking medications that lower the seizure threshold * taking any of the stimulants, thyroid medication, or steroids * implanted devices/ferrous metal of any kind * history of seizure or seizure disorder * inability to determine motor threshold. * Pregnant females and children under the age of 18 will be excluded for safety reasons * No vulnerable populations or special classes of subjects will be considered for participation.