Mean (±SD; closed symbols) and individual (open symbols) burst frequency (bursts/minute; panel A), burst incidence (bursts/100 heartbeats; panel B), and plasma norepinephrine (pg/ml; Panel C) in individuals with clinically diagnosed relapsing-remitting MS currently on disease modifying therapy only (MS-DT; ■), individuals with clinically diagnosed relapsing-remitting MS currently on disease modifying therapy and medications for MS-related symptoms that are known to modify central nervous system function (MS-DT/ST; ●), and healthy age and sex-matched controls (CON; ▼). *Significant difference from CON, P < 0.05.