Imagined Head Rotations Facilitate Spatial Memory

Neuroimaging studies have shown great similarities between the cortical networks involved in motor execution and motor imagery. However, none of those studies report data on head or full body motions and only few provide evidence of behavioral consequences of this similarity. Here, we report results from a novel kinesthetic spatial memory task, in which participants encoded a target position by an active, passive or imagined head rotation. During the experiment, participants were seated on a motion platform with a VR headset, which allowed passive motion and head tracking. To compare all three encoding conditions, precision and head velocity in the executions of head movements were analyzed with Bayesian hierarchical generalized linear regression models. We found comparable performance in precision in the active and imagery conditions whereas performance in the passive condition was significantly reduced. Head motion profiles were similar after active and imagined encoding. The results suggest that imagined head rotations provide useful sensorimotor information despite the absence of sensory and motor information during encoding. This can be explained by corollary discharge which is necessary for appropriate motor behavior and is likely also generated when the motor behavior is imagined but not executed.