PURPOSE:: Motor sequence learning is everywhere, such as playing the piano, keyboard input. What are preferentially learned about the sequence in our mind, spatial structure or sequence element properties? Will the learned motor sequence be influenced after rotating the spatial structure? These problems are still ambiguous in previous researches. This study aims to address the role of mnemonic cues properties on motor sequence learning.
METHODS: The study employed a modified paradigm of the serial reaction time (SRT) task in which participants were instructed to tap icons displayed on a touch screen, the popping sequence of these icons overlapped with an unseen two-dimensional geometric figure. The familiarity and presenting mode of mnemonic cues were changed according to different testing conditions, the locations of icons were shifted in testing period, but the motor sequence was identical throughout the study. A total of 120 naive human subjects were separated randomly in five different conditions. After training, their ability to transfer the motor sequence knowledge they had learned in training period was tested.
Results:  The structured motor sequence learning can be split into implicit memory and explicit memory. Geometric-figure-structure and the sequence all could be memorized finally in explicit memory group but not implicit memory group. Structure outlined by the motor sequence is egocentric, the performance is influenced strongly if the topological structure was rotated. Nonetheless other mnemonic cues overlapped can compensate the loss of spatial information. More properties within the sequence have better mnemonic effects, simultaneously, more distinct properties overlapped on geometric-figure-structure has bigger negative priming effects if the learned sequence is changed unexpectedly.
Conclusions: Topology structure running under the sequence obviously plays a dominant role at motor sequence learning rather than overlapped cues properties. An economic processing principle of cognitive resources is used involuntarily in motor sequence learning.