(e.g., switching off the rotation),
transient “after-effects” occur, with trajectories in the
direction opposite to that observed during initial adaptation
(Shadmehr and Mussa-Ivaldi, 1994; Fernandez-Ruiz
and Diaz, 1999). The presence of after-effects demonstrates
that subjects do not merely react to the perturbation
but have learned to alter their planned movements in
the new environment, using a feedforward control strategy.
Memory in adaptation paradigms is also evident in
the form of savings: when subjects are re-exposed to the
same rotation or force field after some time interval,
adaptation occurs more rapidly (Kojima et al., 2004;
Krakauer