Practice in Native Sensorimotor Coordinates Interferes Anterogradely With Learning During Visuomotor Adaptation

AIN STOLKINER, PEDRO CAFFARO, JORGE IGNACIO VILLATA, VALERIA DELLA MAGGIORE

Córdoba Capital

Congreso; XXVIII CONGRESO ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN EN NEUROCIENCIAS; 2013

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 for equating the initial error levels across adaptation and re-adaptation sessions, necessary for determining an improvement in the adaptation slope (savings). Recently we have shown that a relatively small set number of null trials (176) can interfere with memory retrieval, thereby reducing the amount of savings. Here, we aimed to investigate 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 an opti cal rotation of -40º (for 6 blocks of 88 trials per block). The experimental group previously performed a similar number of null-trials (7 blocks), whereas the control group performed only one block. These practice sessions were separated by 15 minutes. We found a decrease in the speed of learning in the Experimental relative to the Control group (Time-by-Group interaction; p=0.04). Our results support the idea that null trials form a memory that can interfere with memory retrieval and new learning.