Inclusion Criteria- Ischemic infarction within the past 2 years post event that has caused hemiparesis or hemiplegia, as self-reported and/or confirmed by medical record.
- Older than 18 years old.
- Upper extremity weakness defined as a score of >11 and ≤56 on the arm motor Fugl-Mayer motor scale.
- Minimal pre-stroke disability defined as a score of <3 in the Modified Rankin Scale.
- Subjects need to be able to follow directions and participate in 2 hours of testing with short breaks.
- Subjects need to be able to provide informed consent.
Exclusion Criteria- Any substantial decrease in alertness, language reception, or attention that might interfere with understanding instruction for motor testing
- Excessive pain in any joint of the paretic extremity (not applicable to severe stroke subjects), as self reported
- Contraindications to single pulse TMS (will be used to measure cortical excitability) such as: history of seizures, unexplained loss of consciousness, any metal implants in the head, frequent or severe headaches or neck pain, any other electronic implanted medical devices such as pacemakers, defibrillators, or implant medication pump.
- Patients who have taken fluoxetine in the past 5 weeks.
- Patients taking any other SSRI at the time of enrollment or in the previous month.
- Patients taking any other medication likely to have adverse interaction with SSRIs (all the medications the patient is taking will be carefully reviewed, as noted below in "Monitoring of important drug interactions").
- Active depression on admission to SRH defined by a score of 24 or higher in the Hamilton Depression Rating Scale (HAM-D)
- Concurrent medical condition likely to worsen patient's functional status in the next 6 months such as: cancer, terminal heart, kidney or liver disease, as self-reported and/or confirmed by medical record.