Figure 1.

General representation of the interplay between supraspinal (primary sensorimotor cortex), spinal (central pattern generators), and subspinal structures (e.g., ankle dorsiflexors) during locomotion. Efferent pathway from the primary motor cortex (M1) descends to the spinal cord to initiate/mediate the gait. At spinal cord level, contralateral ankle flexors and extensors (here represented by the tibialis anterior [F]; and Soleus [E] respectively) are excited/inhibited rhythmically to produce the basic locomotor pattern of gait. Afferent pathway (e.g., originating from the muscles) ascends to the spinal cord and to the contralateral primary sensory cortex (S1) to produce feedback corrections of the locomotor patterns.