Pupil-Indexed Noninvasive Neuromodulation
Vagus nerve stimulation (VNS) is thought to activate neural pathways that release chemicals which promote plasticity and learning. Previous work has shown that the auricular branch of the vagus nerve innervates landmarks on the external ear. Work from the PI's laboratory has shown that electrical current applied to the external ear modulates physiological indexes of brain states implicated in the therapeutic effects of VNS. The broad objective of this project is to better understand physiological mechanisms modulated by auricular stimulation to support possible therapeutic effects in the form of motor learning.
- EligibilityCriteria: Inclusion Criteria:  ALL PROSPECTIVE SUBJECTS:  18-75 years of age  PROSPECTIVE SUBJECTS DIAGNOSED WITH STROKE:  Diagnosis of a single stroke resulting in hand impairment Diagnosis of stroke at least six months prior to the time of participation  Exclusion Criteria:  ALL PROSPECTIVE SUBJECTS:  History of vestibular disorders or dizziness Difficulty maintaining alertness and/or remaining still Pregnant or expecting to become pregnant Diagnosis of neurological and/or musculoskeletal disorder(s) (other than stroke) that affect movement Ocular disease and/or impairment in more than one eye History of seizure and/or epilepsy Implants, devices, or foreign objects in the brain/body that are incompatible with MRI Body size that is incompatible with MRI scanner dimensions  Anyone already enrolled and actively participating in another greater than minimal risk study.  PROSPECTIVE SUBJECTS DIAGNOSED WITH STROKE:  Other impairments secondary to stroke (e.g., attention, cognition, etc.) that would interfere with the ability to understand study goals or follow simple instructions, as judged by the investigators. - HealthyVolunteers: Accepts Healthy Volunteers - Gender: All - MinimumAge: 18 Years - MaximumAge: 75 Years - StdAgeList: Adult, Older Adult