Visuomotor Learning and Proprioception Across Development

Being able to adapt our motor repertoire to novel contexts is crucial for completing even the simplest daily tasks. This can be examined in visuomotor adaptation paradigms where the motor system is challenged to compensate for changes in vision, such as learning to reach to targets on a screen with a misaligned hand-cursor, which our brains do through trial-and-error. A motor command is sent to the arm and a prediction of the outcome is sent back into the brain. This prediction is compared with sensory feedback from proprioceptors and is thought to generate one of the error signals that drives motor learning. This begs the question of whether adaptation processes might differ across development if proprioception is less reliable, as proprioceptive impairments have been found to occur alongside normal aging (children and older adults differ from young adults) and in several neurological disorders. Proprioception is suspected to be impaired in Ehlers-Danlos syndrome (EDS), a group of inherited connective tissue diseases where the most common symptoms are joint hypermobility and chronic pain. In Chapter 2 I explored sensitivity of hand proprioception in EDS as a function of disease severity. In Chapter 3 I further explored proprioceptive sensitivity in EDS by comparing patients’ estimates of hand position to those of controls, and changes in their estimates after participants underwent visuomotor adaptation. Finally, in Chapter 4, I examined whether visuomotor adaptation differs across the lifespan, by looking at several characteristics of learning and comparing them across groups of children, young adults, and older adults that I tested in familiar settings. Together, these findings provide further insight into how the sensorimotor system functions under special developmental circumstances, such as with connective tissue disease, or during early/late stages of life.