The purpose of this study is to determine the effects of TMS on the ANS. The investigator will determine whether single-pulse TMS of the primary motor cortex in the dominant hemisphere in healthy, young adults will affect 1) heart rate and heart rate variability, 2) blood pressure and 3) baroreflex function. This study is foundational in that it will begin to characterize how single-pulse TMS affects the ANS in healthy adults.

The overall purpose of this study is to investigate the effects of TMS on the ANS. Specifically; the investigator aim to determine if single-pulse TMS of the primary motor cortex in the dominant hemisphere in healthy, young adults will significantly affect 1) heart rate and heart rate variability, 2) blood pressure and 3) baroreflex function.

The first purpose of this study is to measure alterations in sympathetic and parasympathetic activation in response to TMS. To do this, we will measure HRV immediately after single-pulse TMS. The second purpose is to investigate the changes in blood pressure in response to TMS and to determine whether the baroreflex, a critical modulator of blood pressure, is inhibited by TMS.

Aim 1: To determine if single-pulse TMS of the primary motor cortex will significantly alter heart rate variability. We hypothesize that single-pulse TMS of the primary motor cortex will elicit an acute decrease in heart rate and result in improved heart rate variability indicated by a significantly decreased LF power and increased HF power.

Aim 2: To determine if single-pulse TMS of the primary motor cortex will significantly alter blood pressure and baroreflex sensitivity (BRS). We hypothesize that single-pulse TMS of the primary motor cortex will elicit an acute decrease in blood pressure by inhibiting the baroreflex.

Inclusion Criteria:

• healthy volunteers between 18-65 years old

Exclusion Criteria:

• pregnant or breastfeeding women
• previous episodes of seizures or fainting
• any implanted metal in their head
• history of migraines
• history of psychiatric disorder (e.g. depression, anxiety, ADHD, bi-polar disorder)
• currently taking medications that may alter autonomic function (e.g. blood pressure medication, depression medication)

healthy adults