Brain-computer interfaces (BCIs) have been used for rehabilitation therapies with promising results in patients with stroke or Spinal Cord Injury (SCI). While well-established for upper-limb rehabilitation, BCI paradigms for the restoration of lower-limb motor function are less well-established. To establish such a paradigm, we investigated electroencephalographic (EEG) brain activation patterns during a Motor Imagery (MI)-based BCI task to operate a Functional Electrical Stimulator (FES) targeting the Tibialis Anterior (TA) muscles. The correlation of EEG spectral power modulations in the high-beta band (18–24 Hz) during MI of the right, left, and bilateral dorsiflexion movements was evaluated across all 16 EEG recording sites in two healthy participants. High correlations were observed in the central parietal region. These findings hold promise for the development of effective BCI paradigms for restoring lower-limb function.