AUTHOR=Song Sunbin , Cohen Leonardo G. 

TITLE=Conscious recall of different aspects of skill memory

JOURNAL=Frontiers in Behavioral Neuroscience

VOLUME=Volume 8 - 2014

YEAR=2014

URL=https://www.frontiersin.org/journals/behavioral-neuroscience/articles/10.3389/fnbeh.2014.00233

DOI=10.3389/fnbeh.2014.00233

ISSN=1662-5153

ABSTRACT=Different mechanisms are involved in the formation of memories necessary for daily living.  For example, different memory representations are formed for the practiced transitions between key-presses (i.e. pressing key “2” after “3” in “4-3-2-1”) and for the ordinal position of each key-press (i.e. pressing key “2” in the third ordinal position in “4-3-2-1”) in a motor sequence.  Whether the resulting transition-based and ordinal-based memories (Song & Cohen, in press) can be consciously recalled is unknown.  Here, we studied subjects who over a week of training and testing formed transition and ordinal-based memory representations of skill for a 12-item sequence of key-presses.  Afterwards, subjects were first asked to recall and type the trained sequence and then to perform random key-presses avoiding the trained sequence.  The difference in the ability to purposefully recall and avoid a trained sequence represents conscious recall (Destrebecqz & Cleeremans, 2001).  We report that (a) the difference in the ability to purposefully recall and to avoid the trained sequence correlated with ordinal-based but not with transition-based memory, (b) subjects with no ability to recall or avoid the trained sequence formed transition-based but not ordinal-based memories, and (c) subjects with full ability to recall and avoid the trained sequence formed both transition-based and ordinal-based memories.  We conclude that ordinal-based memory can be voluntarily recalled when transition-based memory cannot, documenting a differential capacity to recall memories forming a motor skill.  Understanding that different memories form a motor skill, with different neural substrates (Cohen & Squire, 1980), may help develop novel training strategies in neurorehabilitation of patients with brain lesions.