Modifications in the representation and control of finger movement sequences with learning
Abstract
From typing to playing the piano, sequences of finger movements are essential in our everyday lives. To become skilled at any task, takes practice and determination. To remember and perform a sequence of movements, we form an abstract mental representation of it. To estimate our performance accuracy, we usually rely on sensory feedback from our environment. For instance, when playing piano, we pay close attention to the tone that is played. To improve performance, we adjust our mental representation by integrating this sensory feedback. The goal of this thesis was to elucidate how the mental representation and feedback control of finger movement sequences change with training. We first examined whether the mental representation of a movement sequence can be shaped early in training and how this modulation impacts performance long-term. To this end, we used a discrete sequence production task, in which participants performed sequences of finger presses on a keyboard-like device. We influenced participants’ initial representation to be either beneficial or detrimental to performance and estimated how these instructions impacted subsequent performance. Participants’ performance was continuously influenced by the instructions throughout a three-week training period. Only if participants abandoned the detrimental instruction could they improve their performance. Next, we investigated how feedback control changes across training. Using the same task, we probed feedback integration over four days by either delaying or advancing the time at which participants received the sensory feedback from the keypress. We found that the feedback perturbations consistently slowed or advanced participants’ performance on the perturbed press in accordance with the direction of the perturbation. Nevertheless, the amount of behavioural adjustment decreased with training, suggesting a reduction in feedback integration. In both studies, we could show that the mental representation of skilled movement sequences was hierarchically organized. In summary, this thesis provides novel insights into the change in representation and control of finger movement sequences with training.