First study of PhD project published in 2013 on the impact of practice on the development of mental representations of complex action, tracking changes in motor memory over the course of learning, see here.
Findings revealed a significant improvement in task performance, as well as functional changes in the structure of the practice group’s mental representation. In contrast, no functional adaptations were evident in the mental representation of the control group.
It’s the only hard copy of a journal article I own so far.