RT Journal Article
SR Electronic
T1 Overcoming Motor “Forgetting” Through Reinforcement Of Learned Actions
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 14617
OP 14621a
DO 10.1523/JNEUROSCI.2184-12.2012
VO 32
IS 42
A1 Lior Shmuelof
A1 Vincent S. Huang
A1 Adrian M. Haith
A1 Raymond J. Delnicki
A1 Pietro Mazzoni
A1 John W. Krakauer
YR 2012
UL http://www.jneurosci.org/content/32/42/14617.abstract
AB The human motor system rapidly adapts to systematic perturbations but the adapted behavior seems to be forgotten equally rapidly. The reason for this forgetting is unclear, as is how to overcome it to promote long-term learning. Here we show that adapted behavior can be stabilized by a period of binary feedback about success and failure in the absence of vector error feedback. We examined the time course of decay after adaptation to a visuomotor rotation through a visual error-clamp condition—trials in which subjects received false visual feedback showing perfect directional performance, regardless of the movements they actually made. Exposure to this error-clamp following initial visuomotor adaptation led to a rapid reversion to baseline behavior. In contrast, exposure to binary feedback after initial adaptation turned the adapted state into a new baseline, to which subjects reverted after transient exposure to another visuomotor rotation. When both binary feedback and vector error were present, some subjects exhibited rapid decay to the original baseline, while others persisted in the new baseline. We propose that learning can be decomposed into two components—a fast-learning, fast-forgetting adaptation process that is sensitive to vector errors and insensitive to task success, and a second process driven by success that learns more slowly but is less susceptible to forgetting. These two learning systems may be recruited to different degrees across individuals. Understanding this competitive balance and exploiting the long-term retention properties of learning through reinforcement is likely to be essential for successful neuro-rehabilitation.