Title: The Effect of Explicit Processes on the Generalization of Adaptation
Supervisors: Dr. Romeo Chua
Committee member: Dr. J Timothy Inglis, Dr. Hyosub Kim
Abstract:
We are constantly exposed to dynamic environments where movements must be adapted to changing task demands. Our body’s ability to adapt our movements to meet novel task demands (i.e. muscle fatigue, external forces, reliability of sensory information) is crucial in successfully maneuvering everyday life. To optimize performance, we utilize conscious strategy concurrently with our sensorimotor system recalibrating subconsciously. This recalibration transcends the exact conditions it originally occurs in and generalizes to varying movement parameters depending on the similarity to the original conditions.
Experimentally, movement errors can be artificially imposed during reaching movements by rotating visual feedback of the hand. After repetitive exposure to rotated visual feedback to allow participants to reach an adapted state, we can probe the degree of adaptation around the reaching environment to measure the generalization of motor adaptation across space. To parse apart conscious and subconscious processes, previous studies have utilized the method of getting participants to report where they are aiming prior to performing a reaching movement. The aim report provides an estimate of the degree of conscious strategy that the participant is utilizing as they are aiming off the target to counter the visual rotation of their feedback; however, it may affect the subconscious component of adaptation. Explicitly having to indicate your aim prior to executing your reach may result in a greater focus on the location you are aiming at, rather than the actual target, confounding the findings of implicit adaptation.
The proposed study will determine if the act of aim reporting affects implicit adaptation and the generalization of implicit adaptation across reaching angles. This will be examined through a reaching task with rotated visual feedback and the goal of getting the rotated cursor to the target. Probe trials to targets at various angles with the goal of getting the participant’s hand to the target will be interspersed to capture isolated measures of implicit adaptation. It is hypothesized that the aim reporting group will have the greatest implicit adaptation around the average aim location while the control group will have the greatest implicit adaptation closer to the target where they initially adapted. The findings of the proposed study will potentially influence the interpretation of previous studies that utilized the aim reporting protocol as well as the design of future studies intended to examine the generalization of explicit and implicit sensorimotor adaptation.