Inclusion Criteria:

• Inclusion Criteria (control participants):
• * Be 45-90 years of age
• * Have adequate language and neurocognitive function to participate in training and testing
• * Be medically stable to participate in the study
• * Be English speaking
• Inclusion Criteria (participants with stroke):
• * Be 45-90 years of age
• * Clinically defined, unilateral, hemiparetic stroke with radiologic exclusion of other possible diagnosis
• * Stroke onset at least 6 months before enrollment
• * Subcortical stroke (ex: internal capsule, deep white matter of posterior frontal lobe)
• * Present with mild to moderate arm dysfunction
• * Be medically stable to participate in the study
• * Be English speaking

Exclusion Criteria:

• (for both groups)
• * Unable to give informed consent
• * Have a serious complicating medical illness that would preclude participation
• * Contractures or orthopedic problems limiting range of joint motion in the potential study arm or other impairments that would interfere with the study activities
• * Visual loss such that the subject would not be able to see the test patterns on the robot computer monitor
• * Unable to comply with requirements of the study
• * Enrollment in another greater-than-minimal risk study
• * Presence of medical condition or implant that prevents safe administration of TMS or MRI
• * Pregnancy