To successfully manipulate objects in one's surroundings, such as when lifting a cup, one must accurately perceive their physical interactions. This includes accurately interpreting the tactile cues arising at one's fingertips when touching an object. Currently, tactile perception is assessed in individuals with stroke using passive protocols. Research has yet to explore whether activating one's muscles impacts the tactile perceptual process in individuals with stroke despite previous research demonstrating the effect of muscle activation on tactile perception in individuals who are neurologically intact. The proposed research will be the first to address the impact of muscle activation, in addition to stroke, on tactile perception. As such, the proposed research is significant for advancing our understanding of the extent to which tactile deficits occur in individuals with stroke, particularly during volitional movement.

Participants will detect an externally-applied electrical stimulus at their fingertip with the elbow: 1) relaxed and flexed to 2) 25% and 3) 50% of their maximum voluntary torque (MVT). We will compare the detection threshold for these three conditions between each arm of participants with stroke and similarly-aged controls. Based on pilot data, we hypothesize that the detection threshold will be largest at the paretic arm when flexing to 50% MVT due to the greatest inhibition of sensory signals. Findings will indicate whether stroke negatively impacts an individual's ability to detect tactile stimuli during volitional sensorimotor tasks.

Inclusion Criteria:

• For the participants with stroke, i) a single unilateral cortical lesion that took place at least one year prior and ii) an absence of comorbid neurological impairments
• Ability to understand and complete the experimental tasks
• Capacity to provide informed consent
• At least 18 years of age

Exclusion Criteria:

• Major injury to either arm
• Sensory neuropathy