R01.Aim 2.Study 1: IsoReach

Inclusion criteria, neurotypical participants * 18 years old No history of stroke Ability to provide informed consent . Exclusion criteria, neurotypical participants Severe medical problems (including cardiovascular, orthopedic, or neurological) Medical problems affecting movement, range of motion, strength, or coordination of the upper extremities. Visual deficits that would influence the ability to perform the experiment . This will be assessed using the following assessments: 1. Visual field deficits will be assessed using the BIVABA acuity testing. (cutoff score \> 20/100) 2. Depth perception deficits will be assessed using the Stereofly test (require at least an angle of stereopsis at 16 inches is 3,552 seconds of arc). 4\) Blood pressure above 140 systolic and/or 90 diastolic mmHG 5\) Blood oxygen reading of less than 92% by finger pulse oximeter testing. Inclusion Criteria , Stroke participants * 18 years old Chronic stroke (8+ months post) Available medical records and radiographic information about lesion locations Hemiparesis Primary motor cortex involvement Some degree of both shoulder and elbow movement capability Exclusion Criteria , Stroke participants Bilateral paresis Aphasia, cognitive impairment, or affective dysfunction that would influence the ability to perform the experiment, This will be assessed using the Mini Mental State Examination31, with cut-off scores (adjusted for education level) as follows: Participants whose education are 7th grade or lower, a score 22 or lower Participants whose education attainment level is 8th grade or some high school (but not a graduate), a score of 24 or lower Participants whose education attainment level is high school graduate, a score of 25 or lower Participants whose education attainment level is some college or higher, a score 26 or lower Visual deficits, and hemispatial neglect that would prevent the participants from seeing the targets. A vision test will be done if the participant indicates in their screen that their stroke has affected their vision. This will be tested using the following assessments: Visual field loss will be assessed using the BIVABA acuity test10. (cutoff score \> 20/100) Visual Extinction and Inattention using Star Cancellation Test9. (cutoff score of \<44) Depth perception deficits will be assessed using the Stereofly test (require at least an angle of stereopsis at 16 inches is 3,552 seconds of arc). Modified Ashworth score of 4 at shoulder or elbow joints. Rated below 15 on the FMUE scale Inability to provide an informed consent severe current medical problems Severe sensory deficit in the affected limb (Cannot be absent in any part of affected UE) diffuse/multiple lesion sites or multiple stroke events Inability to attain and maintain testing positions Botox or other botulinum toxin injection to the affected upper extremity within the previous 4 months Concurrent participation in upper extremity rehabilitation either as part of a research intervention protocol or a prescribed therapy Neurological, neuromuscular, or orthopedic diseases (i.e. injuries to your affected arm or hand) Other neurological issues (Parkinson's, CP) Blood Pressure above 140 systolic and/or 90 diastolic mmHg Blood oxygen reading of less than 92% on finger pulse oximetry testing.