Tibialis anterior muscle: instantaneous signals. Slight dorsiflexion of the foot.

Tibialis anterior muscle: instantaneous signals.

Upper panel: longitudinal differential signals under each column of the electrode grid.

Lower right panel: three-dimensional (3D) representation of the instantaneous differential voltage on the surface of the tibialis anterior during a 40 ms (0.040s) time interval.

Grid of 5x12 electrodes of 3mm diameter spaced by 8mm (32 x 88mm).

Acquisition rate: 2048 frames per second.

Reproduction rate: 40 frames per second (500 times slower) with image interpolation.

Two motor unit action potentials can be seen: the first MU is under columns 1-4 (activated after 5ms), the second is under columns 4-5 (activated after 30ms).