Many skilled motor behaviors, such as playing the
piano, are comprised of a sequence of movements.
Sequence learning encompasses at least two distinct
components: the effector-independent acquisition of
the order of elements in the sequence, and the effectordependent
achievement of skilled performance of each
element in the sequence. Experimental paradigms of
sequence learning include the serial reaction time task,
in which subjects are unaware of a repeating sequence
embedded within the task, and learning is measured as
a reduction in response time (Nissen and Bullemer,
1987; Goedert and Willingham, 2002). In another commonly
used paradigm, subjects are asked to learn a short
sequence of movements, and learning is measured as an
increase in speed and accuracy of the movements (Karni
et al., 1998; Walker et al., 2003). A third approach combines
the two components of sequence learning by asking
subjects to explicitly learn a sequence of movements,
thereby allowing for separate quantification of both the
explicit acquisition of sequence order and performance
(speed/accuracy) measures