Variable practice with lenses improves visuo-motor plasticity

Novel sensorimotor situations present a unique challenge to an individual's adaptive ability. Using the simple and easily measured paradigm of visual- motor rearrangement created by the use of visual displacement lenses, we so ught to determine whether an individual's ability to adapt to visuo-motor d iscordance could be improved through training. Subjects threw small balls a t a stationary target during a 3-week practice regimen involving repeated e xposure to one set of lenses in block practice X2.0 magnifying lenses), mul tiple sets of lenses in variable practice (X2.0 magnifying, X0.5 minifying and up-down reversing lenses) or sham lenses. At the end of training, adapt ation to a novel visuo-motor situation (20-degree right shift lenses) was t ested. We found that (1) training with variable practice can increase adapt ability to a novel visuo-motor situation, (2) increased adaptability is ret ained for at least I month and is transferable to further novel visuo-motor permutations and (3) variable practice improves performance of a simple mo tor task even in the undisturbed state. These results have implications for the design of clinical rehabilitation programs and countermeasures to enha nce astronaut adaptability, facilitating adaptive transitions between gravi tational environments. (C) 2001 Elsevier Science B.V. All rights reserved.