Motor learning relies on both feedback and feedforward mechanisms to keep progressive optimization of motor behaviors in a coordinated manner. Error correction based on the fronto-parietal loop is subject to error information inherent within visual feedback. On the other hand, cerebellar activity for restoration of efferent copy involves in operation of feedforward mechanism. Therefore, the amount of error feedback and excitation of cerebellum are keyed to effectiveness of motor learning. Although postural training is of empirical value to prevent falling from the elderly, yet none of previous studies have ever been devoted to improve effectiveness of postural training via manipulations of visual error feedback and cerebellar stimulation.
From the aspect of cognition-motor interaction, the present proposal is a three-year project intended to promote effectiveness of postural training for the elderly. In the first year, feedback-based training benefits from a dynamic postural task under the conditions of different visual size of error feedback (error-reducing feedback, error-enhancing feedback, and fixed error feedback) will be contrasted. In the second year, feedforward-based training benefits from a dynamic postural task by application of cerebellum transcranial electrical stimulation (ctDCS) of different modes (direct current vs. noise vs. sham) will be contrasted. In the third year, the proposal will examine whether postural training with combined approach (error-enhancing feedback and ctDCS) could result in a superior training benefit to those of error-enhancing feedback alone and ctDCS alone approaches. In addition to innovative training intervention, this proposal will make use of current non-linear analyses on EEG signals and postural sway with graph analysis and heading analysis, respectively. It is expected to gain additional insight into behavior and brain mechanisms underlying learning-related changes with the postural training, potentially lending to a more effective training paradigm for postural stability of the elderly.
