Motor imagery and execution activate similar finger representations that are spatially consistent over time

Finger representations in the sensorimotor cortex can be activated even in the absence of somatosensory input or motor output through mere top-down processes, such as motor imagery. While executed finger movements activate finger representations in the primary sensorimotor cortex that are spatially consistent over time within participants, the stability of top-down activated finger representations remains largely unexplored. Given the increasing use of top-down activated sensorimotor representations to both plan implantation of and control brain-computer interfaces, it is crucial to understand the stability of these representations. Here, we investigated the spatial consistency, and thereby reliability, of finger representations activated through motor imagery in the primary somatosensory and primary motor cortex over time. To assess this, participants performed imagined and executed individual finger movements in two 3T fMRI sessions that were [~]2 weeks apart. We observed highly consistent univariate finger-selective activity clusters and multivariate vertex-wise activity patterns within participants over time in both the motor imagery and motor execution task. Using a multivariate across-task decoding approach, we further found that motor execution and motor imagery activate similar finger representations in both the primary somatosensory and primary motor cortex. This demonstrates that motor imagery can be used to identify finger representations related to movement execution. Our findings not only validate the use of top-down processes for brain-computer interface planning and control, but also open up new opportunities for the development of sensorimotor training interventions that do not rely on overt movements.