The Influence of Neural Stimulation on the Acquisition and Consolidation of Bimanual Coordination Tasks

Abstract

The ability to learn and remember previous events has allowed individuals to thrive and become quite skillful in various ways. Experiences can be encoded, stored, and retrieved after a process called consolidation. The purpose of the two experiments reported was to determine how non-invasive brain stimulation can potentially impact the consolidation processes supporting the formation of motor memories of a rhythmic bimanual motor skill after a short bout of practice. To explore the consolidation process, the experiments manipulated the mechanical degrees of freedom (Collaborators et al.), stimulation-training coupling, and time delay for the retesting period. The results from both experiments indicate that rapid performance improvement occurred as a result of training with concurrent augmented feedback in the form of a Lissajous plot. However, the DoF required to complete the task seems to impact the dependency on visual feedback to detect and correct errors in performance after only a short bout of training. Need something on the fragility of motor memory in experiment 1. When the mechanical DoF was reduced in Experiment 2, participants were able to maintain similar levels of performance during the retest when visual feedback was removed. A key feature of the learning process is identifying how the stability of a pattern changes across practice and the extent that consolidation occurs as measured through the accuracy and stability of a recalled pattern. A novel finding of Experiment 2 is that participants were able to produce the target relative phase after both a 2-hr and 6-hr delayed retest in the absence of visual feedback. This indicates that consolidation processes were establishing a motor memory for the trained action. A main area of interest for both experiments was how the use of non-invasive brain stimulation (tDCS) might affect training performance and the consolidation process of a novel rhythmic bimanual skill. In experiment 1, an effect of stimulation timing (before or during training) was found for early in practice where stimulation before training increased the rate of performance improvements. No effect of stimulation was found for Experiment 2. Previous research has presented conflicting findings regarding the validity of this form of non-invasive brain stimulation, and the present studies do not present any robust findings to help clarify any of these blurry lines.