On the content of sensorimotor representations after actual and motor imagery practice.

We examined the similarities between actual and motor imagery practice with regard to the development of sensorimotor representations. Participants had to reproduce knee joint positions (15 or 150 trials) in visuo-proprioceptive or proprioceptive conditions (Experiment 1) or in visual, proprioceptive or visuo-proprioceptive imagery conditions (Experiment 2), before being transferred in a proprioceptive condition. A familiarization session in a proprioceptive condition was performed before imagery practice only (Experiment 2). Results showed that the effect of vision withdrawal varied according to actual or motor imagery practice: performance accuracy in transfer decreased after actual visuo-proprioceptive practice while it increased after visuo-proprioceptive imagery practice. These results suggest that different movement representations can be developed following actual or imagery practice. They also suggest that information from previous experience could be stored in a sensorimotor memory and could be fundamental for the efficiency of motor imagery practice.