Noninvasive VNS to Facilitate Excitability in Motor Cortex

Not Applicable

Completed

Interventions: Device: Transcranial Magnetic Stimulation
Device: transcutaneous auricular vagus nerve stimulation (taVNS)

Brief Summary: Transcranial Magnetic Stimulation (TMS) positively influences motor rehabilitation in stroke recovery. Transcutaneous auricular vagus nerve stimulation (taVNS) has shown effects on cortical plasticity. We investigate whether combination of TMS and taVNS is more effective at motor cortex excitability than either modality alone.

Detailed Description: The investigators aim to determine the effects of taVNS on motor cortex excitability. The hypothesis is that taVNS alone (sham rTMS + active taVNS) will induce increases in motor cortex excitability (post-stimulation compared to baseline). The investigators expect these changes will be of a lesser magnitude than those of TMS alone (active rTMS + sham taVNS) due to the indirect mechanistic approach of taVNS. Another aim is to determine whether taVNS-paired TMS is more effective at inducing cortical excitability than TMS alone, as it is hypothesized that pairing two forms of neuromodulation (active rTMS + active taVNS) will increase TMS-induced cortical excitability in the motor cortex when compared to single modality approaches (active rTMS + sham taVNS; sham rTMS + active taVNS). Furthermore, it is expected that this increase is timing sensitive, and the paired approach will induce larger TMS-induced cortical excitability compared to unpaired neuromodulation (active taVNS + active taVNS).

Recruitment & Eligibility

Inclusion Criteria

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.

Arm && Interventions

Group	Intervention	Description
Active taVNS, Active TMS	transcutaneous auricular vagus nerve stimulation (taVNS)	-
Sham taVNS, Active TMS	Transcranial Magnetic Stimulation	-
Active taVNS, Active TMS	Transcranial Magnetic Stimulation	-
Active taVNS, Sham TMS	transcutaneous auricular vagus nerve stimulation (taVNS)	-
Sham taVNS, Sham TMS	transcutaneous auricular vagus nerve stimulation (taVNS)	-
Sham taVNS, Active TMS	transcutaneous auricular vagus nerve stimulation (taVNS)	-
Active taVNS, Sham TMS	Transcranial Magnetic Stimulation	-
Sham taVNS, Sham TMS	Transcranial Magnetic Stimulation	-

Primary Outcome Measures

Name	Time	Method
Safety of Combined taVNS and TMS	every 10 minutes following for 30 minutes	We will monitor and record adverse events of combined taVNS TMS intervention.

Secondary Outcome Measures