Prediction error in implicit adaptation during visually- and memory-guided reaching tasks

Abstract

Abstract Human movements are acquired by motor adaptation in order to maintain their accuracy. There are two systems in motor adaptation, referred to as explicit or implicit adaptation. It has been suggested that the implicit adaptation is based on the prediction error and has been used in a number of motor adaptation studies. This study aimed to examine the effect of visual memory on prediction error in implicit visuomotor adaptation by comparing visually- and memory-guided reaching tasks. The visually-guided task is thought to be implicit learning based on prediction error, whereas the memory-guided task requires more cognitive processes. We observed the adaptation to visuomotor rotation feedback that is gradually rotated. We found that the adaptation and retention rates were higher in the visually-guided task than in the memory-guided task. Furthermore, the delta-band power obtained by electroencephalography (EEG) in the visually-guided task was increased immediately following the visual feedback. Our results suggest that the prediction error is larger in the visually-guided task, which contributes to updating the internal model to enhance the implicit visuomotor adaptation effectively. In contrast, the prediction error could be attenuated in the memory-guided task due to voluntary and cognitive processes.