Inclusion Criteria: 1. Age: 50 and older 2. PPA diagnosis 3. Native English speaker Exclusion Criteria: 1. Unable to provide consent 2. Taking alpha 2 agonists (clonidine and guanfacine) 3. Other major psychological or neurological diagnosis 4. Major head trauma that contributed to their condition 5. Allergic reaction to adhesives 6. Uncorrected vision/hearing impairments 7. Diabetes 8. Reactive airway disease 9. Untreated hypothyroidism 10. Bradyarrhythmia 11. Unexplained syncope 12. Pregnancy (assessed verbally on the days of MR imaging) 13. Drugs that interact with propranolol, such as alpha 2 agonists 14. Claustrophobia, inner ear implants, aneurysm or other surgical clips, metal foreign bodies in eye, pacemaker or other contraindication to MR scanning. Subjects with any implanted device that cannot be verified as MRI compliant will be excluded.