Training in native coordinates interferes anterogradely with adaptation to rotated visual feedback

J. VILLALTA, A. STOLKINER E. VIGNETTA, V. DELLA MAGGIORE

Washington, DC

Congreso; Annual meeting of the Society for Neuroscience; 2014

Society for Neuroscience

Motor adaptation is a type of motor learning that allows maintaining accurate movements in the presence of environmental or internal perturbations by creating new sensorimotor maps. A typical experiment involves a session of familiarization during which subjects move to a visual target in native -unperturbed- sensorimotor coordinates (null trials), followed by an adaptation session to a visual perturbation. Often, null trials are used in savings protocols to equate the initial level of error across adaptation and re-adaptation sessions (to ?wash out? aftereffects)[1]. Recently we have shown that a relatively small number of null trials (2 blocks of 88 trials) presented just before the test session can interfere with memory retrieval, thereby reducing the amount of savings [2]. Our results suggest that practice in unperturbed conditions is not innocuous but may lead to the formation of a new visuomotor memory. Here, we addressed this hypothesis by investigating if, like perturbations, null trials can directly interfere with new learning. To test this hypothesis we trained two groups of naïve subjects on a visuomotor adapation task to a -40o optical rotation (6 blocks of 88 trials). The experimental and control groups were preceded by 7 and 1 blocks of null-trials, respectively. We found a decrease in the amount of memory retention measured 1 min after adaptation in the Experimental relative to the Control group (p=0.04) . Our results support the idea that null trials form a memory that competes with those formed during adaptation to rotated visual feedback. [1] Krakauer JW et al. J Nerosci. 2005 Jan 12;25(2):473-8 [2] Villalta JI et al., Cereb Cortex. 2013 Dec 19. [Epub ahead of print]